Happened to me too yesterday I had many alt and my account where I do European activism got shadowbanned so I decided to delete everything but they would not let me, the only way is to cause mayhem and break the rules to make them regret keeping you.

I think schildichat on matrix is a good alternative the app is developed by a German guy and matrix is decentralized as the fediverse you can have your own server or join a mass server.