How many Senate Republicans will vote to convict Biden in his impeachment trial?

[Attorney General, LGC Speaker, and Former PPT Dwarven Dragon]

First off, lol at the OP being a doomsday scenario. In reality, Hassan is safe, the Nomination of Masters is far from guaranteed, Murkowski almost certainly gets saved by Alaska's Top 4 RCV system. Dems going 0-4 in PA/GA/NV/AZ also seems exceedingly unlikely. I'm legit surprised you didn't throw in "whoever replaces Bennet" or something.

Moving on, I'm not even sure impeachment passes the House - some Republican Al Green writing up articles won't get the votes, leadership will need to devote time to it which they may not want to do, and secondly, even if it does, I doubt it clears 30 votes in the Senate, even if we assume the doomsday scenario. Under a (far more likely) 51-49 R Senate with Kelly (or a Non-Masters R) and Murkowski still there, may not even clear 25. Remember that McConnell didn't just support certification, he whipped in favor of it - while McCarthy was whipping against it. And most will follow McConnell's lead. Obviously if Dems keep the Senate (still very possible), Schumer probably just forces through a motion to dismiss.