There’s currently no way to migrate accounts between lemmy instances. I know that this capability is one of the main feature requests, so hopefully the developers can add it at some point in the near future. Not only would it allow users to migrate if they have advanced warning that their instance will shut down, but it would make it easier to spread users out amongst the federated instances to avoid there being only a few “main” instances.

Is there any intrinsic value to an account anyway? There isn’t even an accumulated karma value, so really all there is is the posts and comments you’ve made. Presumably those would disappear along with the server they were hosted on, but I would like to know about comments posted under posts from other instances.