Thats what I meant. The admin is the person that most always has your data but data breaches are other people getting in which is not that hard to prevent. You dont have to run faster than the bear… just faster than the guy next to you.

For signal we assume that native connections are e2ee, for whatsapp I‘m less sure thats really the case and for discord we know that nothing is encrypted.

So yes, if someone got into the server and started poking around undetected, one might have their signal texts laid bare. I‘m pretty sure the likelyhood isnt as high as a phone getting hacked, especially for small servers that are obscure.

In any case, you do you.