Another worry I have and has not been stated above is this:
Biden wins but Republicans keep 51 in Senate. After the election Mitch argues that the nominee should be somebody acceptable to both Biden and Republicans, and they end up choosing somebody right of even Garland.
I suppose this is somewhat parallel to RGB's nomination too since she was on Orrin Hatch's list to Bill Clinton, but people are much more careful in dissecting a nominee's past now.
I don't think there are judges to the right of Garland that would be acceptable to Biden, & I don't think even Garland would be acceptable to Biden anymore considering his age, but a judge to the right of RBG wouldn't necessarily be a bad thing given, for example, Kagan replacing John Paul Stevens wasn't the end of the world.
In this case, I could see Mitch getting pressure from Mitt Romney, Lisa Murkowski and/or Susan Collins (if she survives) to allow Biden a more liberal pick since the overall court ballance isn't affected by the pick (liberal replacing liberal). In case the election actually ends with 51 senate Republicans, I'd still hope Murkowski switches to Independent caucusing with the Democrats. I mean, she has little chance to get reelected as a Republican in 2022 anyway.