I think yt-dlp allows you to use your browser’s cookies to appear as a signed in user for downloading videos. I never bothered trying that.

How easy is it to make a throwaway google account nowadays?

I make throwaway Google accounts semi-frequently, though I don’t remember what they require. If you have a phone number it’s definitely sufficient but I don’t remember if you can make one without a phone number. If they require a phone number you can just buy a cheap sim card (in cash if you care about privacy) and use that. It costs money so if you need hundreds of throwaway accounts maybe not, but if it’s just one for downloading videos then it’s probably NBD, you’d be spending money on the VPN anyway.

yt-dlp hasn’t worked for me for a few months on Mullvad. Using Swiss and Swedish servers but I’ve tried a couple other countries too, same problem.

If/when I have money to spare, I share that money by a function of how much I use a piece of software, and how much the project needs funding (so a combination of costs vs income). So generally the projects I donate most to are the ones I use daily, and also are either more obscure or more expensive to maintain.