I think most who want NSFW in their feed simply subscribe to things from here https://lemmynsfw.com/
It's an instance only about NSFW. Elsewhere it is rare, yes. I think that's honestly good for Lemmy.world and others. Even if OP's suggestion on image hosts is good, if it blows up I expect a ton of people will begin uploading 4K porn directly on the instance.
So, anyway, as usual with subscribing from another instance, you go here and search for [email protected] if what you need is more boobs, then subsribe to that and voila it's as if it was here on lemmy.world.