the casinos and on line gambling (POGO) were supposed to be a money maker for the government and provide jobs for locals. These organizations started under President Aquino but expanded under president Duterte.

the local Catholic bishops opposed these, not just because of the corruption that they inspire, but because they seduce poor local women into the sex industry.

Ah, but Wikipedia notes that it has been a windfall for importing Chinese citizens into the Philippines.

It was reported as of October 2019 that 470,000 people were employed in the POGO industry, with total annual payroll at $9 billion. These might included more than a hundred thousand Chinese workers

the fact that some of these young men might be soldiers in the Chinese military is an open secret.

President Marcos family comes from the Northern Philippines, so theoretically he should know who she is (he denies this, but hey, there are a lot of mayors, so maybe he doesn't recognize her)...

Lots of holes in her story (She doesn't speak the local language of the town where she is a mayor, for example, and her claims of homeschool ignores that such students have to be associated with an outside school who certifies such studies), and there are lots of other paperwork discrepancies.

so what party sponsored her? 

Wikipedia says she was an independent candidate. 

So how could she win? Well, as Lolo used to say about politicians: They are all crooks. So locals, figuring they are all crooks, just vote for the highest bidder.

given her connections with various scams in the Philippines one suspects that maybe this is more about money than spying.

Rappler has a list of the holes in her story.

the POGOs are not just about employing often illegal foreigners who might be spies or military but are about laundering money and even stealing it. And then we have them involved in hacking the Phil Government websites.

the corruption of the POGOs is not new: GMA article from 2020 reveals 14 billion pesos (3 billion USD) in suspicious transactions

as for national security: MSN resports:

Small Town in the Philippines Shocked by Accusations Against Mayor Alice Guo of Being a Chinese Spy as she could not explain her background during Inquiry.

the money laundering, sex trafficking, and other money making scams associated with the POGO in her town raised suspicions:

Law enforcement recently uncovered that this Pogo centre was a front for a large-scale scam operation, where 700 workers, including 202 Chinese nationals, were rescued from being forced to pose as online lovers.

nothing new about this: so why should a small town mayor's lies about her background and a common corruption scandal erupt into a major scandal? 

Strategic Location of Bamban EDCA sites are joint US-Philippine military facilities, created through the two countries’ Enhanced Defence Cooperation Agreement, that allow for the rotational presence of US troops. Bamban is located 30km north of Basa Air Base, one of the country’s nine EDCA sites Bamban, a quaint town located north of Manila, has become the epicenter of a national controversy following allegations that its young mayor, Alice Guo, is a Chinese agent. The accusations surfaced after Mayor Guo’s contentious testimony at a recent Senate hearing, which raised suspicions about her background and activities.