When I've seen Watson play, which hasn't been that often and includes his relatively poor game against the Chiefs this year (QBR of 45.1), he looks like a good QB to me, a winner. Right now, he's ranked 9th in QBR (
https://www.espn.com/nfl/qbr). Of the 8 QBs ahead of him, he younger than 6 of them. Mahomes is 3 days younger and Josh Allen is 9 months younger than Watson. I think Watson is going to get even better than he already is, because experience really helps most talented young QBs get better and better.
You can see his 2020 splits here:
https://www.espn.com/nfl/player/spli...deshaun-watson