With the vlemmy situation ongoing, i feel like it would be useful to put this here (i did not make either of these tools)
Lemmy Account Settings Instance Migrator (LASIM) copies all your subscribed communities and blocks and lets you upload them to another account, in just a few clicks
lemmy-migrate does the same thing but without a GUI and support for uploading your backup to multiple accounts at once
This is the first I’ve heard of LASIM, love that it copies blocks as well. I’ve been using lemmy-migrate and I don’t think there’s any options for block lists but otherwise it works really well across multiple accounts