I'm using 2019 because I hate 2021, even though its brush tool does work just fine. 2019 is aslo a tad laggy. I did just upgrade to Big Sur, on a 2014 iMac, so maybe that's part of the cause? I'd really rather not downgrade back to Mojave, as Big Sur fixed so many issues I've been having. And I have so many PS preferences saved, I'd so rather not have to reset them. But any ideas for a fix, I'm all ears!
ALSO, while you're here, after upgrading, NO photoshop icons are displaying in Finder. They only show the photoshop icon and not the actual thumbnail. I hate this. Fixes?