From the map, you can see Shantou Guandong is guarding the bashi channel between Taiwan and Philippines.
Almost all US forces entering South China Sea from Japan bases or exiting South China Sea will pass through near Shantou, bashi channel or taiwan strait.
Shantou has a naval base but its hardly heard of. SSF you most heard is hainan Sanya but its too western side , too far away.
I think China should put Carrier CV 18 at Shantou , guarding the entrance. In case of conflict , it can quickly intercept US and its allies.
Additionally, a carrier force from there can quickly go to Taiwan south side and east side where it's less defended than the western side.
A number of times, US reconnaisance planes or B2 Bomber from Guam entering through Bashi channel and approaching China.
Also, if US submarines come in they also go through bashi channel. Chinese diesel subs can wait for them on the western side.
If China put major airforces , including J20 at Shantou, it should intercept US airforces from Guam.
China North and East fleet are too boxed in with limited mobility.
Hainan is too western side, away from the main stage.
Therefore , hands down, Shantou guarding the Bashi channel and near Taiwan, is China most strategic location. But people hardly talk about it.
I expect China to change that and put 1 or 2 carriers force there to guarding the entrance and exit of South China Sea,. Also including major air force and submarine force as well.