Looks like the us is slowly changing its strategy in the scs they already realized how vulnerable there carriers is and now starting to utilize strategic bombers with standoff weapons
What should China response be? I think China should invest more in interceptors, uav, and missile defence systems to counter the us
Yes. The US was slow in realising the significance of the SCC islands and by the time it did, China had already moved to utilise them so as to make the SCC a trap for any hostile naval power. I think the Spirits are are attempt to show power, but they of little real value.
Impressive though they are in their own way, they are aircraft from another era designed for the wars of another era. Furthermore the fleet is tiny, only 20 Spirit class aircraft were built, as the US correctly realised that with the end of the cold war, the type was pointless. Despite the US obsession with stealth, its advantages are largely limited to avoiding tracking from enemy fighters. An advanced, near-peer enemy using ground or ship based air defence systems (or AWACS) would have little trouble targetting a stealth aircraft, especially one like the B2 which has no ability to run or evade, and also no ability to fight back.
Any good, modern anti-aircraft defence with radar optimised for VHF/UHF band operation should do the trick. In their air they are helpless, and they can only operate from well-equipped ground bases so their operations are predictable. That said, since there's so few of them, I doubt the US will attempt to run any sustained patrol or campaign utilising them. They are eye watering expensive to operate and need a *lot* of downtime for maintenance in dedicated facilities. B52 and B1s are both more capable, more flexible and far more numerous, and cheaper to operate. Any air based patrol/sabre-rattling programme will likely switch to them. A few intercepts and escorts of some B2 flights just to make the point the PLAN / PLAAF can track them would be a good way to send the message, "We can see you". These flights should make a point of using Subi or Firey Cross as bases to reinforce the message that China does have the islands, that the islands aren't going anywhere, and that they are a meaningful force projector for both the PLAN and PLAAF.