Ever since his breakout hit "Fancy Like," Walker Hayes has had more high points than the Himalayas: his first headlining arena tour and now an even bigger one just launched, a best-selling book, a 70,000-seat sellout at the Houston Rodeo, a CMT artist of the year award, not to mention Grammy, Billboard, ACM and CMA nominations.

So why — if you ask him which experience has been the most life-changing — can he not stop talking about Rwanda?

Last month, the 43-year-old artist, his wife, Laney, and their six children traveled to the central African nation on a mission Trip, and those 12 days, he says, poured so many life lessons into him that "it's gonna take me years to sift through."

The journey was at the invitation of HOPE International, a faith-based nonprofit that has assisted 2.7 million people in 20 underserved countries with "microfinance" initiatives, small loans and savings services that help people to help themselves. Each day the Hayes family visited a different HOPE site in Rwanda, getting acquainted with the work, listening to people's stories, pitching in with their own muscle and sweat, and embracing every outside-their-comfort-zone moment.

"The trip," Hayes tells PEOPLE, "was an answered prayer. Every day for that entire trip was the best day of my life."

He admits that, when he and Laney first talked about how they wanted to spend their downtime between tour obligations, their first thought was where they could go "to just decompress." That didn't last long.

"We just thought the last thing we needed was some resort," he says. "We've tried that, and it's funny … We go to relax, and usually we end up spoiled and stressed and not happy at all."

For years, Hayes and his best friend and former pastor, Craig Allen Cooper — who collaborated with Hayes on Glad You're Here, their popular faith-based book released last year — had discussed going on a mission trip together. Cooper's wife is a HOPE operations manager based in Nashville, and the Coopers had traveled to Rwanda before, so planning a trip there was a natural choice. Logistics were quickly set in motion for both families, including the Coopers' four children, to make the trip together.

From the start, Hayes understood "it wasn't a vacation," and he confesses, he was initially nervous. But a conversation with HOPE's CEO, Peter Greer, quickly set his mind at ease.

"I didn't know what I had to offer," Hayes says, "I was like, what's my purpose? And Peter said, 'You're just going to encourage those working over there,' and I knew, I can do that."

The group made the capital city of Kigali their home base, and every morning they piled into a bus to head out into Rwanda's lush, hilly countryside.

A trip to a family's coffee-growing enterprise left an especially memorable impression on Hayes. "We were invited into their home, and we prayed for the day," he recalls. "They took us to the fields. We all picked coffee beans. We sang the songs they sing out in the field. We peeled the beans, and then we stood in a circle, and we pounded them in this bowl — it took your whole body to grind these beans. And then we roasted them. We went through the entire process the whole day."

While pounding the beans, he says, he thought about the electric grinder sitting in his kitchen at home and what such a device might mean in this moment. But he also began to reflect on what his consumer lifestyle could be costing him.

"They don't have the basic things that we have," Hayes says, "yet their contentment is overwhelming. They have a faith that is just unhindered by a lot of things we might call blessings in our country, but I don't know if they are."

The entourage visited homes without plumbing or electricity, and one day, they helped their hosts haul water from a distant well. Hayes watched in awe as his children — three sons and three daughters, ages 7 to 17 — didn't seem to notice the deprivations.

"Their focus was how cool their clothes were, how cool their songs were," he recalls. "'How do they balance those baskets on their heads?' They met friends just like they do here in the U.S. where kids kind of stare at each other for a couple of minutes, and then before you knew it, they were off just playing. We went down to the well, and I looked over, and [9-year-old] Lolly was just lost in a crowd of kids chasing a frog."

Another day, the group was introduced to a woman whose first step to self-sufficiency, as a single teenage mother, was joining other young unwed moms to scrape together 20 cents a month as savings. Today, 15 years later, the woman supervises a clothing and textile business that employs 20 single mothers who are all able to care for their children with their income.

Hayes recalls: "She basically stood up and just said, 'Look, I was ashamed. My parents were ashamed of me. My community was ashamed of me, but Jesus wasn't.' And so while coming to faith in Christ, she's also broken the cycle of poverty, and HOPE facilitated that. We were all in a puddle."

During their time in Kigali, Hayes took some of his children to visit a museum and memorial dedicated to remembering Rwanda's 1994 genocide, when 600,000 to 800,000 civilians in the Tutsi ethnic group were massacred by Hutu militias. Absorbing the history of this bloodbath and its aftermath of reconciliation, Hayes was even more overwhelmed by the spirit of fellowship he had been encountering among the Rwandans.

Hayes' 17-year-old daughter, Lela, was similarly moved. "She said, 'So Dad, there's people living in Rwanda now who were killing people. They're living next door to each other now.' And honestly, as an outsider, you don't feel that anger. They seem so unified compared to the U.S.," Hayes says, with a wry laugh. "Their forgiveness is large. God is just large over there."

Not unsurprisingly, music played a major part in the group's experience, but it wasn't Hayes'. He obliged the HOPE staff's request for a rendition of "Fancy Like," but otherwise he didn't perform — and didn't even bring a guitar along on the trip. Instead, he reveled in the songs he heard everywhere he went, especially in worship.

"When they lift their voices up to the Lord in song, it is different," he says. "It is alive. Here, if somebody starts twerking in the aisle, you're like, what's going on? But over there, if you're not dancing, you're the oddball out."

Hayes was touched, at the end of the trip, when his 11-year-old son, Beckett — the most reserved, "camera-shy of the entire bunch" — said "the dancing" when he was asked what he'd miss the most about Rwanda.

"That destroyed me," Hayes says. "That was proof right there that the trip was an answered prayer — just dragging this cliché family out of our bubble. That was one of the most magnificent moments."

Beckett's response came during a sharing time that Craig Allen Cooper had initiated for the travelers. "I asked them three questions," Cooper explains. "What are you gonna miss the most? What do you want to bring home with you? And what have you enjoyed the most?"

He reads the responses from the other Hayes children, which his wife, Laura, thought to jot down: "How welcoming it is here." "The joyfulness of the people." "The smiles." "The Rwandan joy." "The simplicity of life."

And then Cooper shares what Hayes, surely in the throes of processing his experiences, said in this intimate moment: "It's so easy to forget yourself here. I'm just thinking about Jesus here, not success and the future. There's no telling what the impact will be."

Today, Hayes is still wrestling with that unknown, though he's already taken one big step, setting aside a time during his concerts to introduce his audiences to HOPE International and send them to a website he's created for them to connect to the work.

Still, he doesn't think that's enough. "I feel compelled to continue on this journey," he says. "What else can I learn? What other organizations are out there? What other countries can I see? Not like it's a bucket list, but just, what is my purpose here outside of myself?"

These questions are far different from what he was asking himself just two years ago, when "Fancy Like" blew up so unexpectedly, putting his career in a steep upward trajectory after 15 years of stumbles and almosts. At the time, he couldn't help but wonder, why him? Why now?

Today, he says, he's at peace with those questions: "I didn't get here on my own, so obviously God wants me here. I have a very strong feeling of contentment about where I am."

His Rwanda experience has taught him — just as obviously — that contentment doesn't mean he can get comfortable, particularly with the trappings of success. "It's funny, we can literally have whatever we want," he says, "but I'm not sure what we want is what we need to want, if that makes any sense. One thing God has really done with Craig and our families is we've begun to be drawn to the awkward, the uncomfortable. … Discomfort can be the best thing for you. As a matter of fact, most of the time it is."

All the while, his star continues its trajectory. A day before he was headed out to his first tour date, Hayes was counting his blessings — grateful that his songs and stage presence keep connecting with audiences; grateful that his career is now supporting his band, his crew and so many other people who have helped him get to this place; grateful that once again Laney, the kids — and their three dogs — are joining him on his tour bus.

"We're excited to get on the road together," he says. "We're actually tightest on the road because we're in a bus, so we're kind of like a bear family hibernating."

This time around, Lela will be along in an official capacity: The chief choreographer and co-star of Hayes' viral "Fancy Like" TikTok dance, she's now on stage as one of her dad's backup dancers.

"I don't take that for granted that I get to work with my 17-year-old daughter that close," he says with fatherly pride.

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Hayes says he's feeling "a little more relaxed" for this second arena tour after shaking off some jitters from his first. "There's less apprehension and hesitation, like, do I belong here? Am I good enough?" he says. Now he knows "people will show up, and I'm just gonna share with them what I can."

He's beginning to get accustomed to his own "unhindered" moments onstage, which he says tell him, "I'm pretty sure this is where I was born to be. Like, right now, this is it."

Still, he also believes the journey to Rwanda is ushering in a new chapter for him and his family, and he's eager to discover where it takes them.

Says Hayes: "It's just incredible to be a part of whatever God's doing right now through us."

Hayes' 23-date "Duck Buck" tour launched last week in Rosemont, Illinois, and ends June 16 in Round Rock, Texas.