The app that synchronizes multiple lemmy accounts so you can migrate and keep backup accounts across instances, it's opensource and free, currently working in android and windows.
It's in homologation now and anyone can test, any feedbacks are welcome as always.
Think of each instance as its own reddit, except that if you have an account on one "reddit", you can also access the subreddits (called communities or comms here) of another linked (federated) "reddit".