Who are plausible Biden nominees post KBJ?

[President Johnson]

Sri Srinivasan would be a top-contender, I guess. I'm relatively certain it would be a man this time around. If Roberts retired for example, I could also see Biden elevating Sotomayor to Chief Justice and replace her seat with a new appointee.

Hopefully, a Republican Senate will refuse to confirm all Biden nominees.

So a future Democratic senate should also refuse to confirm any of Trump/DeSantis or some other Republicans' nominees?

[President Johnson]

Sri Srinivasan would be a top-contender, I guess. I'm relatively certain it would be a man this time around. If Roberts retired for example, I could also see Biden elevating Sotomayor to Chief Justice and replace her seat with a new appointee.

Hopefully, a Republican Senate will refuse to confirm all Biden nominees.

So a future Democratic senate should also refuse to confirm any of Trump/DeSantis or some other Republicans' nominees?

I think the opposite actually.

1. The optics of appointing a man to a seat formerly held by a woman would be terrible for Biden.

2. If he gets to fill another seat formerly held by a man, it would be the decisive seat to have a majority-female SCOTUS for the first time in history.  There would be huge pressure for Biden to do this.   

Fair enough, at least should he have to replace Kegan or Sotomayor.

Unfortunately, I doubt Biden will get another appointment in this presidential term. Maybe during the next, which would require the Democrats to keep the senate until at least to the 2026 midterms. Possible? Yes. Likely? No.