Unless something has changed, migrating your account is more like copy/pasting config on a new account. Your post history etc however does not come with it. If that’s something that matters to you then picking the “right” server matters a little bit.

For example lemmy.world has defederated from a bunch of instances (https://lemmy.world/instances) Creating your account there means you’re missing some of the full experience of Lemmy, for better or for worse. A smaller instance may federate more content, but may run slower or worst case stop working entirely if the admin abandons it.

I just used a handful of different servers over the course of a few weeks to see which was my ideal server.