Heya!
In 'settings', there should be an option to enable/disable adult content from showing up in the store! https://itch.io/user/settings
That that should prevent such content from showing up while browsing things!
Edit: Ah, upon looking on a SFW account, I think I see what you mean now. Even when games are hidden in main searches, the tags and games associated with the tags can still show up on the tag page, often with NSFW covers even if you have NSFW disabled.