I kind of want to move over to lemmy.ml because I don't like the content in lemmy.one if it helps I also deleted my lemmy.ml account because I signed up for both and thought I could only have one. Going to the lemmy.ml website now says 404 deleted and I want to fix that.
"The content" on all Lemmy instances is the same. There is no account migration, but you can just sign up on lemmy.ml. If you already had an account there and you want it back... I don't know if it's possible for an admin there to restore it, you might have to get in touch with them.
This is really the core element people seem to be worried about. You build a community, you post a heap of content, you have charge of moderation and then suddenly your chosen instance dies, or you get banned.
I think there will eventually be a fix, but encourage everyone to remember that this, the biggest weakness of the platform is also its greatest strength. Personally I have created my communities on a different instance than the one I post on daily. It's a larger instance and the only thing on that account are post submissions - I use lemmy.dbzer0 to browse and comment daily because I like its interface and local community the best.
It annoyed me at first, but I've learned to see the value in having separate yet interlinked spaces. I have also duplicated that community and some content on another instance. It has zero traffic, but I don't trust anyone or anything these days.