You can export your lemmy account settings and then wipe the instance and install Piefed on the same domain and import your settings.

But you will lose your replies etc that way, and at least for 24h other instances will refuse to federate with your instance, but apparently after that they realize the instance has changed and will accept the new keys.

There is one former Lemmy instance that did it this way: https://quokk.au/ and apparently it works fine now.

For the subscriptions Piefed can import the Lemmy user export, no? Or am I misremembering that being a feature already?

We plan to work on a possible migration script or so at the end of the year. But it will take time and I am really not an expert on these things. If you want to help out investigating the database structure etc. you are more than welcome.

I am currently thinking that a stand alone python script to copy over the data from a Lemmy database to a fresh Piefed instance would be the best, but migrating the pictures from Pictrs would be another problem then…