how exactly does further colonization by the Chinese mainland help with [Taiwan decolonized, the place names of the Austronesians reestablished, the nation of Austronesians self-determined and self-governing]

Because of the way contradictory historical processes actually work. Chinese integration is not a process of colonization, it is a process of resolving the contradiction of Western imperialism. Western imperialism imposed a contradiction on top of the Han Chinese settler colonial contradiction. Resolving the Western imperial contradiction creates the conditions necessary to resolve the Han Chinese settler colonial contradiction.

Your focus on the specific Austronesian ethnicity is IMHO extremely racist, and restoring them as the sole inhabitants would be nothing short of a genocide of a large part of the current population that chose peaceful democratic coexistence in the last couple of decades.

I thought you just said that it was settler colonialism and not peaceful coexistence. Now suddenly saying that Han Chinese occupation is settlerdom is racist? That's like saying it's racist against white people to deny them sovereignty over the territories in the Western hemisphere. Stop the duplicitous pearl clutching. The 16 Austronesian nations of the major islands that comprise Taiwan province are not Taiwanese by nationality any more than the Lakota, Dakota, Seneca, and Navajo are American.

a large part of the current population that chose peaceful democratic coexistence in the last couple of decades

Peaceful coexistence under the "protection" of the most genocidal violent psychopathic military empire in the world. Listen, this would sound very compelling if it wasn't for the fact that US defense analysts and officials have spent years talking about the Pacific Kill Chain, Kill Web, and Hellscape infrastructure they are trying to build on the island of Taiwan. It would be compelling if the US didn't have special forces stationed 2 miles off the coast the mainland.

But if you actually look at what's happening, your story of peaceful coexistence is a lie by omission. Yes, all of the people of the province want peaceful coexistence, as do all of the people and nations in China. And China is an incredibly peaceful nation - no bombs dropped since 1989, no boats fired on since 1988. The majority of the world understands that peaceful coexistence is only possible after the vast genocidal white supremacist Western empire falls and their military presence is removed from the four corners of the Earth. Taiwan has peaceful coexistence except for that little nagging problem of literally being part of a genocidal empire's infrastructure for mass murder. I know it's a little nit to pick, but I'm gonna pick it.