This is something I raised in the Itch Discord server but I'll put it here as a reminder.
So, if an user is either logged out or has adult content disabled then they shouldn't see NSFW games on Itch, that's what one would expect. And, for the most part, things do work like that without an issue.
Recently I found an issue: if you go to a game's Related Games section (here's Deltarune's as an example) while logged out you'll be shown a collection of games — even the NSFW ones. I haven't checked this with an account with adult content disabled but, even if that's working, the issue I raised requires attention.
Speaking as a game dev working on adult content, I don't like the idea of children coming here looking for games like Deltarune and then being exposed to/recommended multiple adult games. I don't think this is right and it cannot go well.