I've wondered if he might eventually get the 25th amendment treatment

There is a zero percent chance of that happening - ever. The President gets to pick his own cabinet. Then those people are going to - en masse - turn around and vote him out? Never, absent a car accident which leaves him in a vegetative state.

I feel the same way about Impeachment conviction. Unless that vote were to be taken anonymously, the voters of whichever party would have to face the constituents who put them in office, which means they would succumb to primary challenges from within their own party, thus rendering their vote a suicide mission.

Neither of those removal procedures is viable, there needs to be something different. Absent “anonymous vote” for conviction, I don’t know what it is (that also has protections against simple majority expulsion, which would render the position dangerously susceptible to political machinations.)