My way of creating mature stuff that’s as not “cheesy” or “edge lord-ish” as possible is, separating what I make happen in the story and how explicit the way you convey that event is in the artwork.
For example, I can write a story of a guy looking for love.
This simple concept can be used to create both family friendly and adults only content.
To make it dark, violent or sexual, I shall express the character’s journey with depictions of flirting, kissing, having sex or arguing with his partner.
On the other hand, if it was supposed to be for younger audience, the methods above should be replaced with depictions children can understand easily.
I strongly believe that the plot, universe, characters, goals and all the stuffs forming the show must not be vulgarity itself but something “meaningful”. It’s, like I’ve said, the way you show how everything goes. If a story is all about someone hooking up with multiple girls, the show is very likely to end up being like garbage such as Paradise PD and other Netflix’s generic comedy shows. They claim to be funny and dark at the same time but we perceive them as childish while being so kid-unfriendly.
Since I don’t know what you exactly want to make, finding out how you will create using this technique is your job. Hope what I said helps.