So I actually forgot that I also made a fedia.io account back when I was trying multiple instances...there were literally like 100 people on fedia.io at the time so I stuck with kbin, but then kbin kinda imploded so I switched to lemmy...
We have the same issue at fedia as lemmy.cafe - single overworked administrator.
I do see comments that say it's possible to block instances on mbin, but I don't see any way to do that on fedia.
Haha, I got it! It's not anywhere in the settings at all, lol. Like a hidden option. You have to go to the url "https://fedia.io/d/[instance domain name]", like "https://fedia.io/d/lemmy.ml". Then it will give you the ability to block, and that block will be reflected in your settings page.