The KB5121767 update was an out of band update Microsoft released specifically for Dell devices that had a bug, and KB5101684 is an optional preview update that is basically an early beta version of the August update and those optional preview updates may contain bugs.
1
Open the updates section in the Settings app.
Below the updates is a switch to 'Get the latest updates as soon as they are released', disable that option and restart your PC, that will stop the optional updates installing on your PC.
2
Then to undo any problems caused by those updates, in the Settings app, go to System Recovery.
Click the 'Reinstall Now' button in the 'Fix problems with Windows Updates' section and wait for that process to complete.