Was Trump losing a blessing in disguise for the GOP?

[TML]

Yes in the sense that the person who defeated him is not a fighter (FDR and LBJ are what I would consider "fighters"), but not necessarily in the sense of getting the party to shift gears to broaden their appeal (and the latter may very well limit their gains as long as Trump remains relevant).

[TML]

Of course it was and Joe Biden winning was a disaster for Dems.  They should have seen it coming (I did) and just let Trump win in 2020.  Once RBG died and Trump replaced her, pretty much any good  reason for Dems to want Biden to win went out the window.

Democrats have pretty much had three Presidents in a row that have progressively destroyed the party more and more downballot (Clinton, Obama, and Biden). 

I don't think that's necessarily true. Exit polls from 2020 indicated that Biden won the group which considered SC appointments an important factor. Additionally, if Trump got to replace any of Breyer/Sotomayor/Kagan, that would make the rightward tilt of the court much more significant, so in that sense letting Biden replace any of those three can be seen as "damage control" which is still better than the alternative.