>Yeah at some point in the past I had it mostly working. But basically now, what should I do? Maybe host a VM with an actual browser (not headless: just the real thing) and log into a Google account and then what, use yt-dlp from the same IP?

What I've been doing is sshing to my main pc running fedora that has a legit firefox with my google/youtube cookies, have a distrobox with archlinux on it, entering that machine and then running yt-dlp there. Since distrobox has mounts your host /home dir into the guest /home it can easily source cookies from your host pc.

The reason for Archlinux is that it seams to do a much better job than Fedora at keeping yt-dlp updated and with the necessary dependencies to successfully download videos. So this synergy between your main machine (where google cant't tell you are "illegitimate") + a guest machine with the "clandestine" software (in google's view lol) all stitched together by distrobox works well.