The process is actually weirder than that. Each state’s delegation gets one vote, collectively. Republicans would probably still win. (It’s the new Congress that does the election rather than the current one but rural states count the same as California so Republicans have a built-in advantage.) They can only choose between the top 3 candidates.

For VP, the Senate votes — I think one vote per Senator, as per usual. So, if everything is the same post-election and a party-line vote, we’d have a Trump - Kamala Harris administration. She’d remain VP and cast the tying votes in the Senate but presumably wouldn’t do anything with the White House.

Also, if the House is deadlocked 25-25 on Inauguration Day, the current VP becomes President. So, we’d have President Kamala Harris until the House broke its deadlock.