At this stage in the game, I'm not even sure how to evaluate the trustworthiness of instances. Which also applies to the one I'm currently on. I'd like to assume everything is good, but admins do have power that can be abused, like visibility of IP addresses, access to accounts, access to passwords (reusing passwords is bad but especially don't do it here and certainly don't use the same password for your email associated with your account).

Facebook abused those powers (zuck even bragged about being able to see everyone's passwords, emails, private messages, pictures), so did Reddit (though more with shadow banning or quietly removing/restoring posts).

Fediverse instances are just run by random people as far as I can tell. I'm sure there's some that should absolutely be avoided and I'm sure that there's some that are perfectly fine. But I don't have a clue how to determine which list about specific instance is in, otherwise I'd love to join someone's small instance.

Edit: oh and that only goes into whether the admin is acting in good faith or intends to be abusive. Then there's the question of whether the admin is competent enough to run a server without it getting pwnt and giving others access to that same information and capabilities.