Field standby has been in use recently on the 777 SFO. It's available to the crew desk, so it happens.

As far as the base goes, 777 has lots of domestic flying. Not as efficient as international and many domestic trips are not commutable, sometimes on both ends so the domestic flying goes junior. Plan on being on short call. Long call doesn't happen much.

The SFO 777's go pretty much everywhere. Europe, Pacific. It's also used as a tool for beating up competition. Just put a cattle car A model with a gazillion seats to compete. So flying changes frequently.

The big question is how will HKG and the rest of China come back. Will the Chinese stop using Covid as an excuse to keep other airlines out? No idea.

The 787 trades some flying with the 777 seasonally, flies longer routes, and the thinner markets. Not nearly as much domestic flying. But as has been said, we are getting new 787's, and for now the 777 fleet is stable.