Kit - 1/16/2023 09:56
Make sure your Windows 11 install is updated to the 22H2 version. You can check this by right-clicking the start button, going to System, and looking for the version number in the middle of the window. When Windows 11 first came out, Microsoft somehow broke the file explorer in Windows 11, and it could be incredibly slow at times. I've never seen it do anything like what you describe, but I have seen it suffer huge lag when manipulating large/many files.
If you are on the 22H2 version, it might be worthwhile to run a hard drive scan to check its integrity.
First thing I did, and no errors found. I simply shut down the machine after several hours of hanging on that task, and the problem disappeared.
The problem never reappeared. In retrospect, it's not much of an issue, but it was very frustrating at the time.