@kauer They are IP blocking public invidious instances, which are a frontend for searching for videos on youtube.
invidious is quite useful, as it allows for searching for videos and being able to access links posted with the video without running proprietary malware JavaScript on your computer; https://www.gnu.org/philosophy/javascript-trap.html
invidious can also be used for watching videos, although yt-dlp generally gives a better experience.
So far private instances haven't been IP blocked and it seems that to use it in the future, people will need to start self-hosting invidious and only share their instance with a few close friends.
@mononoaware Yes, to host videos, you can just put a .webm on your website, or to GNU mediagoblin and/or make a .torrent for that file, or upload to a peertube instance, but that won't allow you to access videos on youtube.