No, it doesnt just come down to wall. The other things you mention are great. I give credit where credit is due.
But I felt he caved on the wall. He should have vetoed that damned bill. If congress overrode it, then so be it. Its on congress....The wall is not a small issue. It is one of his main themes he ran on. He has to fight for it.
If you were able to read the notes or following articles a day after he signed the bill, there were poison clauses about funding. As an example, Planned Parenthood will only get funding THRU the OMB, which is held by Trump loyalists.
There was a reason why Trump sent the infamous letter to Paul Ryan, which may be the reason why he needed to retire NOW. In it, it summed up a subtle summary that “you may have stabbed me in the back but I got you”.