But can I transfer a user from one to another? Or do I lose all my subscriptions and such?

You can’t “transfer a user” to another instance but you can transfer your subscriptions (including blocked users, blocked communities, saved posts, saved comments) and account settings. Go into your settings page (probably lemmy.world/settings) and then, on the right hand side above the Delete Account button, you’ll see a section where you can Import/Export your settings as a .json file. Do that, then go to a new instance, create an account there, and then upload that .json file into the import box in the same area (the one that says Browse…) on your new account at your new instance and then hit import.

It’s super simple. I hope I explained it adequately.

You can have all three under communism.