I don't think Abrams would help him carry Georgia, so he'd be wasting a VP pick. He should pick one that could help him pick up a battleground state.
Besides that, Abrams is pretty much toxic with indies, IMO.
Only Black that can stop the Biden bleeding is Mike. Tulsi took out Harris for good.
It looks to me that the only viable candidate the dems can field that will secure the black vote is Hillary, the wife of the first Black president. I'm not sure Joe realizes it or not, but he's between Hillary and the presidency, and he just fucked up big time.