If you can’t update macOS to 11.3, do the following:
- Launch Photoshop.
- Go to Preferences > Performance > Advanced Settings and uncheck the Use OpenCL checkbox.
- Restart Photoshop.
If you cannot start Photoshop to complete step 2 above, restart your computer then try again.
For more details, https://helpx.adobe.com/photoshop/kb/photoshop-and-macos-catalina.html
Thanks,
Akash