Yeah, agree with Joe, Perchance is decent for explicit photos, though it does have it's quirks. If you're looking for video you might need to research into paid programs. Though I have no interest so it's not something I've looked into myself.
For the writing, honestly there's so many other ways to look for ideas then using an AI. There's the forums here and on other sites. Like Reddit has a ton of NSFW prompt subs - make a throwaway account if you don't want it linked to an account you already have. Plus, on Reddit they even have subs for people who want writing advise or to talk with people - again, this is including NSFW groups.
For flow help, you can look up story guides/structures -- There are MANY. Ugh, too many. I honestly don't think it would be inappropriate to ask something like chatgpt to create a writing structure guide for you if you know what you want and don't want. Say you wanted a story guide that combined the 3 act structure with the plot pyramid, and have it add in a suggested word count per section with a max of 4,000 words - it will do that for you. It's not writing the story for you but giving you a guide to plop in your ideas and see the areas you need to fill out even more or where you need to cut things back. That to me is okay since it's a guide you'd use to plot out your writing just like in school.
Also, say you want a better word to use, you could ask something like chat. I know there's thesaurus sites but they lack context. So for example I just put this into chat: "I'm writing a spicy story, can you give me other words to describe my main characters husbands blue eyes?" and there's a ton of answers but they're all simple like this: pale sapphire, midnight blue, cobalt, etc. Using those wouldn't be plagiarism/letting AI write for you. However, asking chat to write the thoughts of the wife describing her husband's "cobalt" eyes and then using those prompts would be.
Grammarly is what I use for grammar control. I like it because it does teach you as you use it. I don't use PRO, though I have in the past for my academic writing, but as long as you aren't abusing the auto-rewrite/write features, it's okay. Just know that it's pretty easy for AI-written things to be identified - Grammarly has an AI detector and checks for plagiarism, too. It does a lot more than just that but say you are writing your own stories, then plop it into Grammarly, or use the keyboard sensor to check spelling/grammar etc, that's fine. Like right now there's suggestions all over my text because I use the extension for Grammarly, but this is my casual typing so I don't want this to sound like my formal writing, but for it to sound like me instead.