I haven’t heard anyone badmouth him either. Post 2021, I put the blame on ownership. We had better rosters than 2019 (2014 and 2017 come to mind) and they didn’t win.
Have there been any truly bad managers that have won rings? Hell, only 4 current managers have won the World Series: Bochy, Roberts, Francona and Hinch. It’s hard to do. Davey had his flaws, but I’m giving credit where credit is due.
As for Grisham, we are remembering incorrectly. Even without his error, the Wild card game would have been tied. And winning it all requires some luck. Nats had plenty of bad luck and didn’t win in the past (again, think 2014 and 2017). It’s hard to begrudge them the time they got some good luck. The Dodgers needed some to win last year and everyone thinks they are a juggernaut.