I don't see disturbing stuff that often, usually few times a year, but it's usually some very disgusting csam.
Most of the time it's just spam and trolls, but from time to time these degenerates show up.
It doesn't really have any lasting effect on me, I kinda manage to not think about it at all. I guess my aphantasia helps here as well, I think it's much harder for folks who can visualise things in their mind.
Can you report it? My vague understanding is that the laws of the country where the server is hosted apply, so hopefully the police would have resources to investigate.
We can and we do. Though I wouldn't expect much out of it. I live in the EU and while it's great at many things, being quick to act is not one of them.
CSAM is the reason I wouldn't consider self hosting tbh. I fear it could result in me having hundreds of GBs worth of the stuff without me even noticing.