I'm not sure where the idea that China should go aggressive against Philippines comes from. Philippines is harmless, and even in the best case scenario there's not a whole lot that China can gain from a conflict. There's a reason why China only uses the Coast Guard in this region.
And really the same goes for just about any other combat theater. None of them offer anything particularly valuable for China's strategic position so they're all non-starter. The only thing that China would feel is worth fighting for is Taiwan, and it will have to be taken first before anything else is considered.
Harmless?
All the US bases that they are reopening and expanding, all the US missiles they are hosting in the Batanes is harmless?
Attacking the Philippines is about teaching a weak power a lesson that their current approach is foolish and counter productive. If you don't teach them a lesson, then countries like Vietnam get further ideas about challenging China and allying with US and Japan.
China's current timid approach is not reducing either western hostility or hostility of China's neighbours. Cause no one takes them seriously. China is seen as too timid or their military is seen as useless since no one has seen it perform.
I think China should stop the hide and bide and start the Sino-Monroe doctrine soon. It will improve China's position in the world, they will be treated with more respect and fear. This will in the end reduce the conflicts they will have to fight. Its also time to show so called US security guarantees are completely toothless and useless against China.