I would test a full UI reset - you can return to your original settings afterwards if it doesn’t help.
**Important First Step - If you have the Curse/Twitch - ElvUI/Tukui or similar addon manager/installer - temporarily uninstall. (Those will interfere with the test)
Close game completely. Navigate to the main Wow folder > retail folder. Rename the Cache, Interface and WTF folders to .old — Cache.old - Interface.old - WTF.old
The game will install new folders on launch. Test with a new UI and no addons. If that didn’t work simply remove the .old from your original folders and delete the new ones the Launcher installed. (This returns your previous settings as they were)
Also run the Scan and Repair tool. On the Battle.net Launcher look for gear cog beside Play button. Open that - tool is there. Takes 10 mins or so to run.
Nothing will be lost when you revert back to your original WTF folder. If it turns out the issue is corruption in the WTF folder then you will be starting from scratch.
Close the Bnet app - then right click the Bnet icon on desktop. Select “Run as Administrator” from the context menu that appears. Once the app is open - try again.
I reinstalled the game and for a moment it seemed the scan was working, then it just started looping on itself. Started rescanning. No error; just said it finished scanning and then starting the repair process… happened 2-3 times before I closed it. running it as admin atm
edit: running as admin didn’t fix it. Still looping the scan and repair. I cannot even open the game at this point
edit2: apparently it was something to do with the data folder. i just deleted it and now i’m able to properly reinstall the game