Blurred UI buttons

I couldn't duplicate the problem on my own system (Mac Monterey). However, problems within the interface can usually be fixed by deleting your InDesign cache files (which is not the same as deleting preferences).

To do so on a PC:

On Windows 7 and above the caches files are hidden. To find them go to the Control Panel and open Folder Options and then click the View tab. Then select “Show hidden files and folders” or “Show hidden files, folders or drive options” in Advanced Settings. Then delete (or rename) the folder at the end of this path: C:\Users\[User Name]\AppData\Local\Adobe\InDesign\Version [#]\<Language>\Cache. I find that deleting the InDesign cache folder completely leads to a lasting change.