How to deal with the Chinese coast guard.
1. The said conflict point is close to Philippines and far away from China.
2. This gives Philippines a massive geographic advantage.
3. Philippines must dispatch all its available ships to Scarborough.
4. Once Philippines establish a numerical superiority, then Philippines must enforce its law to detain the Chinese fishermen by deadly force if necessary.
5. Then the narrative of Scarborough being under Filipino jurisdiction is established, which will influence all future Chinese activities in the region.
You don't see Chinese coastguard ships anywhere near the Chinese claimed areas of Japanese and Korean jurisdiction, because Japan and Korea have established that narrative by the forceful enforcement of their laws, and the Chinese coastguard doesn't dare to challenge this once established narratives, and just sit and watch while Korean and Japanese coastguards detain Chinese fishing boats in Chinese-claimed areas.
So if Philippines backs down now, they stand to lose for generations. Philippines must enforce its laws by force even if that causes a short-term conflict, because the long-term loss is greater if they fear the cost of standing up to China.
Korea built its forward base at Socotra Rocks, ignoring Chinese protest. The Chinese fear that they may have lost the territorial claims narrative against Korea forever due to their inactions.