Be wary of offers to install software on your machine that claim to do the impossible. If "block all adult content" were something easy to do, we wouldn't have entire industries built on providing filtering services to corporations.
It's possible someone could build a browser plugin that blocks all adult-labeled content on itch.io. It won't also work on Steam, or drivethrurpg, or youtube, or vimeo, or AO3, or tumblr, or twitter, or bluesky. They all use different methods to label "adult" content. (And they don't all agree on what "adult content" is.)