Shortcuts (using Cmd+Shift+...?) not working anymore
Hi!
I'm relatively new to the Mac ecosystem (half a year maybe) but already had and still have a very frustrating experience involving shortcuts that just won't work anymore on my Macbook Pro (M1/Big Sur).
Several shortcuts including Cmd+Shift are affected. At the moment, Cmd+Shift+U ([Mark as read] or however it's called in English in Mail) as well as Cmd+Shift+P ([Show All Commands] in Visual Studio Code) come to mind.
I have fiddled around with the system preferences, especially for the keyboard as well as the region/language settings (I'm running a German system so I'm not 100% sure about the English terms). I have set stuff back to its defaults, added and deleted stuff, and of course restarted my machine a couple of times in the process. Nothing worked.
It's not the keyboard. It doesn't even seem to be the combination of keys. When I manually add a shortcut to the respective list in the keyboard section of the system preferences, it recognizes that I enter Cmd+Shift+U, for example. It saves and displays it. But when I want to use it in Mail, it doesn't work. (One curious detail: I added Cmd+U for the same command and it worked. It worked even after I had deleted it again, which is also not quite what I want it to do. Of course not...)
I even started following advice elsewhere that I should get rid of certain apps. Since I can live without them, I uninstalled Zoom and Lightroom, even though I wasn't sure they even bring global shortcuts. I am not aware of having any other software installed that meddles with shortcuts in other programs. (I'm not a big fan of 'productivity tools' that are configured differently on every machine. Further, and more fundamentally, I am also not willing to wipe my entire system because a couple of shortcuts aren't working. That's behavior I would expect from a PC running Windows 98, but not from a Mac.)
So does anybody have more ideas about possible reasons and solutions? I typically rely heavily on shortcuts for repetitive commands so this issue is a real pain. :(
MacBook Pro 13″, macOS 11.2