Thats a problem with silos (where one owner hosts all the servers) in general. You will have to switch the entire ecosystem once the inevitable enshitification sets in. It’s a good idea to switch to something open source and federated (where many different non profit organisations and even self hosting individuals host many different servers). That way you can migrate your history and contacts to another server of necessary but never have to switch the ecosystem again. Xmpp and matrix are the hottest candidates in my opinion, but you can check the messenger matrix that was linked in a comment above to see what suits you best.