Isn’t this always the case? I get people have a hate-on for Windows 11 lately but every major version of Windows 10 has kept the old version for a month or so, allowing you to revert if needed. You can run disk cleanup and get the space back early if you want.

I guess the notable part here is that the disk cleanup part isn’t working? You can also just wait for the time to elapse and it will delete itself.