Can confirm**, in Zoom. I'm guessing Zoom over-rides the Solus settings because Zoom only has one function: camera&audio. In other words why wouldn't it bypass the default?
Could this be the case with Discord? You have privacy camera/audio settings in Discord, I saw the pictures. Maybe you need to double down on the settings.
At least in Firefox I can make it ask me for permission to access. Not in licensed zoom. But that's ok.
**disclaimer: I turned off camera and mic in settings, did not reboot, and launched zoom. possible variable there.