Once you reach the desktop in Safe Mode try running the app having a problem. Applications that run at startup don't run automatically. This allows you to test your app(s) by running them with a minimal set of fonts, an empty font cache, and without potentially conflicting apps running. Only a limited number of fonts are enabled. When you do a Safe Boot Mac OS fixes troubles with your Mac's directory and file system. It will take a long time for your Mac to start up in Safe Mode. M1 Macs have a different way to do a safe boot.
I think the next thing to do is another relatively simple procedure: Perform a Safe Boot by holding the SHIFT key down as your Mac starts up from a restart or shut down. I think the next thing to check is fonts.
