I'd be curious about this too. Pretty sure you can migrate on Mastodon

As far as I’m aware, it’s not possible to migrate to a new server. Not your user account. Or your communities.

I note on GitHub, Some see it as a bug. Others as a feature.

None of that is currently possible - the best option would be to create your new user, then resubscribe to your communities. Bonus: if you use the same username on federated instances, this shows up on your profile.

Given that this is possible on Mastodon, I'd expect to see it on Lemmy at some point.

The devs have spoken about this. Quoting Nutomic:

Or you could just put a link to your old account into your bio. So this might be a useful feature, but very very low priority. // More useful could be import/export of settings and subscriptions (also much easier to implement).

So there are plans to address this in the future, so you don't lose your data from server migration, but migrating the account itself is low priority. (Even then if someone found a way to do this, and submitted a pull request, they'd probably accept it.)

Nah unfortunately that is not possible

In all honesty, its better to a have a few accounts anyway. Imagine your main instance goes down for a period of time or permanently. Your account will go down with that ship. Having a few affiliated accounts across the fediverse will help mitigate user downtime. I've got accounts at Beehaw, lemmy.world, and here at Kbin.

Why do you want them to see your posts and comments so much? The rest of the federation should be plenty of audience, right?

You have fewer than 50 comments. Resubbing is trivial and there is no karma points to accrue. Just make a new account if you desire.