Photoshop 2021 started crashing just few seconds (20/30 seconds) after the startup, even without opening any project.
I updated all of my graphics drivers, tried to force using Graphic processor (GTX 960M) and to force using only the integrated graphics. I tried to reset preferences, reinstall the software after cleaning all cached files. Nothing.
Randomly, I decided to completely disable my integrated graphics card (Intel HD Graphics 530) from the Device Manager and Photshop magically does not crash anymore.
That's a solution but I don't like having my GPU working alone.
I can share with you the stacktrace (the software usually crash without letting me report, sometimes instead I had the occasion to copy the report)
How do you mean when you write, "I don't like having my GPU working alone".
Generally integrated graphics are so you can have a display in the event you Don't have a dedicated GPU, which it sounds like you do. When working with your GPU, and having your monitor connected to the GPU, you're actually not using the Integrated Graphics card much, if at all.
It could be that a driver update the IG card might have a conflict in it and was causing the issues, in which case changing to a different drive could help, or disabling will do the trick. Seems you've done the latter (well done!) and that ultimately will be just fine.
That's a weird situation to explain but I'll try my best: my notebook has a GeForce GTX 960M other than an Intel HD Graphics 530 (that is what I meant for "integrated").
I was doing some research for my specific error that I retrieved in the exception stacktrace and I found (I don't remember where) that someone had some Intel compatibility problem (also mentioned in the stacktrace). At that point, I already had updated all NVIDIA drivers, so I tried updating Intel drivers. Nothing changed until I tried to disable my Intel HD Graphics 530 from Device Manager (Windows 10) and that did the trick. Right now, that's the only way I found.