This is the biggest flaw, as l see it, with Mastodon & the fediverse in general (sure, it's much better than Twitter, etc....But?)
This problem could be solved by having our own unique (& anonymous if wanted) password protected fediverse ID.
So, adimin can kick you off their instance, but they can't delete your online conections.
So, online encrypted ID 👍
Generally, using a similar code as crypto currency wallets.