The rules state that the run has to be done in a private world, runner used a custom world with a difficulty change.

Runner also validated their own run, which I also believe is against the rules.

I saw from the YouTube comments that you already got an answer about the first point but I'd just like to say that it's fine for a moderator to verify their own run. In fact, when a mod submits a run to one of their games the run is set to be verified automatically by default.

I updated the wording of the category rules to clarify, I didn't realise the wording was vague until you pointed it out to me so many thanks, hopefully it's clearer now.