You can just turn off or blur NSFW posts in your settings. Also why when you create an account it asks you if you want to optionally enable NSFW content. That's an already solved problem. You don't need to defederate for that.
then literally just don't check the "show nsfw" content when you sign up. I beg of you just to open your settings a single time and see what's there, it's not complicated.
They're not particularly explicit. Most of them are just talking about sex. There was some toothbrushes that got reported for being too risque once though.
I would recommend keeping the blur on and subscribing and then you can ignore it all unless you're in subscribed and even then it's just suggestive talk of normal looking memes mostly.
Not childporn. There's a community called "adorableporn" that originally had, as part of its description "childlike" (other descriptors were things like "cute") while being very clear that everyone on that community was 18+ (and even validating questionable posts with age verification). The wording of "childlike" has since been removed to ensure no confusion.