On piefed.social I don’t want to have much NSFW content to oversee because it’s an extra moderation burden but there is plenty of it on other instances.
If you go to https://piefed.social/auth/instance_chooser and then filter by ’NSFW content available’ you’ll see the instances that allow NSFW communities. Of those feddit.online has been around the longest and will have the deepest back catalogue but most of them will be fine for casual browsing.
Before you make an account on a new instance, go to the_instance.tld/communities then into the advanced search and switch on NSFW to check how many NSFW communities have been federated to that instance.
I think this is one of the fediverse’s weaknesses. If I host an instance why would I want to risk jail time for failing to moderate an NSFW community? Reddit would just ban the subreddit but if it’s on your local machine I feel the risks are too high.