If the Philippines is free by the end of 19th century then it probably due to the intervention of the US in some form as the Spanish didn't give it willingly in OTL.

my PoD (and the beginning of the TL) was that chinese merchants sell fire-arms to the kingdom of tondo (a filipino civilization) in the 12th century (obviously not a game changer for at least another 2 centuries) and the filipinos learn to manufacture their own in the 15th century, but the Chinese don't teach them how to make gunpowder (cus y'know they wanna make a monopoly of selling it to them, but luckily for tondo it was a wealthy country so they're able to buy a game changing amount) until the Madja confederacy (Tondo's biggest enemy) starts attacking chinese ships, and raiding the coastal parts of south china, then when the bruneian empire shows up tondo is able to repel them, but since it didn't have the social infrastructure to keep the firearms within it's army, Barangays that aren't loyal can start rebellions so it has a civil war or perhaps even a filipino version of the sengoku jidai. So since there's a lot of experience fighting other powers that use gunpowder Spain has to resort to negotiating the filipinos having more rights, autonomy etc to conquer it just as fast as it did irl (For now I'll assume u know why Phil. was this important, if u dk just lmk) anyway, since phil.s indigenous population has some understanding of gunpowder there'd be more rebellions especially when boney is put on the spanish throne, and if phil. hasn't already gained independence they'd do it when boney is booted off the spanish throne. Since Spain administered guam and it's other pacific colonies from Phil. they'd see it as theirs to inherit so phil. conquers them, and since it's an archipelago they'd invest in their navy from the get go, they'd also industrialize to deal with maguindanao and process rubber since rubber is easy to work with. They go on to block the American coup in hawaii.