I downloaded the app mlem and logged into this account, then I opened a link to a thing/group called "technology" or something close to that.
The top post was the was the first time in over 20 years of going online that I saw illegal images. No way to report it, no way to do anything but delete the app. Now I use the browser only. But other than that, kind of ok with a lot walls of text about social media ethics.
Edit: I found the post in the browser and reported it. It was in https://beehaw.org/c/technology