I’ll never understand how Twitch became as big as a thing as it is.
You already answered that in your comment.
You want to watch videos, not livestreams. Of course a video will be better at being, you know, a video (nicely edited, in short format, etc). A livestream is different for many reasons, none of which interests you apparently.
Nothing wrong with that tbh. It’s just not for you.
AFAIK this is not what’s happening this time. YouTube slowly rolled out a change over the past 3 days that requires some sort of app verification for the android yt app. This is affecting Invidious since it emulates the yt android client to fetch video streams. This affects invidious instances hosted privately as well.
The maintainers are aware of this, and are working on ways to solve it. Tools like yt-dlp/newpipe still work because they have working implementations to fetch data by emulating web/iOS/etc clients.