Do you use any security applications? If not, you might want to. The behavior your describing sounds like it could be a result of malicious code, but it might just be a settings issues as well.
I wish I could be more help on the “settings issue” idea. I cannot recall the specifics, but a year or more ago, I was having an issue somewhat similar to what you describe with Empyrion Galactic Survival. One or more of my user inputs was not behaving normally at all, and while it wasn’t as pervasive or interfering as what you describe, it was annoying. It turned out I had a setting in my OS I had flicked for some other purpose (actually I’m remember now . . . I think it had something to do with screen resolution and text size . . .) and this was the source of the “bug.”
If verifying local files / unintalling-reinstalling the game didn’t help, then it might be time to reinstall Steam. I THINK you can do that without wiping all your installed games? Steam tends to phone home to update itself a lot anywyay, so that is not a seemingly likely resolution, just an idea . . .
One would think that fully uninstalling and reinstalling a game would be the “gold standard” to restore it to baseline functionality. However, doing that might be more involved than it seems. I’m not sure about this game or cry engine in general, but some software leave cache files in rando places on your hard drive which can cause problems like this to linger even after a full uninstall-reinstall sequence.
The other thing I’ll toss out there, just an idea again: don’t assume that uninstall-reinstall and verify local file integrity will have the same effects. If you tried on method and it didn’t fix, it might make sense to spend the time trying the other as well.
Beyond all those steps you can do on your end, I’d say it is time to submit a formal bug report along with all the documentation and probably a save file. It may be that a past installed mod has corrupted something and when you remove the application (but not the game directory and wherever the mod/corrupted file lives) you are not removing that effect.