You have to create a new account on a new server then use the account migration tool. It’s not perfect; you’ll keep your followers but I think your posts won’t transfer over. Notes from the tool:
Before proceeding, please read these notes carefully:
This action will move all followers from the current account to the new account
Your current account’s profile will be updated with a redirect notice and be excluded from searches
No other data will be moved automatically
The new account must first be configured to back-reference this one
After moving there is a waiting period during which you will not be able to move again
Your current account will not be fully usable afterwards. However, you will have access to data export as well as re-activation.
Interesting, how did they solve it?
You have to create a new account on a new server then use the account migration tool. It’s not perfect; you’ll keep your followers but I think your posts won’t transfer over. Notes from the tool:
It seems that the answer is complicated. Check this out: https://www.makeuseof.com/how-to-migrate-to-different-mastodon-server/