i did a full apt dist-upgrade to try and get the h264ify plugin to install and if i remember correctly i never was able to get it to install. I upgraded from "chromium" to "chromium-browser" and set all the compositing and other settings recommended for the RPI.

and to reply to another sibling, "yt-dlp" isn't workable, this is for a senior citizen that does small motor repairs.

I got an HP elitedesk that's a few years old coming in monday to replace the RPI; hopefully that will last another 3 years before google et al decide to "optimize" again.

RPI 3 for a senior citizen seems like a poor solution in the first place.

I would have opted for a small business-pc that is x86 based and 3-4 years old.

a used laptop that can play youtube videos can be had for about the same money

ytdl-format=best[vcodec!*=vp9]