The 25th amendment is for cases of incapacity that don't result in impeachable offenses. Trump should be impeached, again, if only so that he cannot run again. Grounds are plentiful, including his corrupt use of the pardon power (which is a power, not a privilege). If Congress lacks the will to boot him from office, that's on us for allowing him to stay in office.

The only remedy for awful presidents is an electorate smart enough not to elect them. Seventy million deplorable and/or benighted souls voted for Trump. There isn't much we can do about the deplorables, but the benighted are on all of us. If we can't beat a Trump soundly, we don't deserve to govern ourselves, because we are incapable of governing ourselves.