1) Is not even close to Flickr. It's way more like Instagram, which is an entirely different and unrelated thing.
2) Barely has docs. Everything just says "to do".
3) Doesn't even have a website! pixelfed.org just says "coming soon" since last year. It has 400 different language translations though, all telling you the same nothing.
How is that in any way superior?
Flickr lets you organize your photos and videos together. Peertube and Pixelfed don't do that. You keep suggesting one-off social sharing feed services, but those are entirely orthogonal to what Flickr and the now defunct MediaGoblin provide.
Your suggested replacements do entirely different things than what they're alleged to be replacing, and at least one of them doesn't even tell you how to run or use it.
git clone https://git.savannah.gnu.org/git/mediagoblin.git
Put it on github and see how everything starts to get better.
Uh, maybe, except that none of the things you list actually do anything close to the core promise of MediaGoblin. MediaGoblin was going to be the libre Flickr/YouTube replacer. Nothing focusing on federation networks has ever gotten even close to that, so it definitely wasn't beaten by those. At best now there's Piwigo, which by the way, is on GitHub.