Can we host it ourselves a la Mastodon / Lemmy / Fediverse stuff?

What part of this is self-hosted?

No, it was mostly short bash/python/php scripts.

I knew a guy who boasted about the number of repositories he created on Github. Said he created over four thousand.

I took a look. He did in fact sit down and create over 4,000 different, unique repositories. Each with a README and some slight variation on a few lines of code. That’s some kind of dedication, I guess?