There's nothing about the content being federated that makes it hard or impossible to index. Each instance is just a website with a public webpage that a bot can read. That all a search engine needs to index it. The worst case scenario is the bot will find the same content on multiple instances.
I did read that the website is loaded entirely through JavaScript and that maybe the Google bot doesn't execute JavaScript so can't see the text. I don't know if that's still a problem in 2023, though.
This article says it's not a problem, but I didn't read past the tl;dr, so maybe there's a caveat. Like maybe it has to use a popular framework like React or something to work.
https://searchengineland.com/tested-googlebot-crawls-javascript-heres-learned-220157
It's barely been a week! Let me grieve!