Similar to this user, I’ve just found that pip install --user doesn’t work for me anymore.
I hadn’t tried updating packages since last month’s big python 3.11 update – where I followed the provided guide as best I could – and now I get the PEP 668 message when I do pip install --user yt-dlp.
I had done pretty much all of my python package installations with the --user flag; for more specialized stuff I used miniconda3 to create environments.
[EDIT: Fixed broken link, typo]