Even national review is starting to openly question if Biden is in possession of his full facilities. They're a fairly restrained, center right publication, it has to be pretty serious for them to be taking this stance.
Something Is Wrong with the President | National Review
The problem is, as
@Airedale260 noted earlier, the democrats don't have any good opitions in response to this. Harris is the VP solely on the basis of her race and gender, if she was a white guy with her background she'd be a minor cabinet secretary at most (which we know because Xavier Barrera, the white dude who replaced her as AG, is now a minor cabinet secretary). She flamed out in the primary largely on the basis of her being spectacularly unlikable and transparently evil, qualities that have not gone away since then, to the point that the DNC powers that be are attemptimg to work behind the scenes to salvage her reputation, without viable success thus far. Harris as the president is unelectable on her own merits.