We are aware that auto moderation may not work ideally, we have received a considerable number of complains there but is not something we can control at this time. You can forward these complains to moderatecontent, which is a third-party service.
You should open/look for an RFC requesting to add another service(s) for the moderation purposes. I don't think that moderatecontent will change its result efficiency anytime soon.
Regarding NSFW filtering, at this time there's no built-in option to do that. You could open/look for an RFC requesting to add such filtering or craft a custom listing for your needs.