You can, in theory, generate a new key for every post if you want to. The relays don't care.
This is something Mastodon etc. lacks (accounts are tied to servers, so you can't move your self-hosted Mastodon to your self-hosted Akkomo without keeping Mastodon running, and you can't move from one instance to another if your instance admin doesn't let you).
On the other hand, the complete lack of account recovery, even for sysadmins, is something many people will have an issue with.