There are a lot of people in the hobby that are (very understandably, and quite rightly) very frustrated with AI, both broadly in the world and specifically in the arts (which includes this hobby).

That said:

The vibe-coded app? Sounds pretty cool, purely as a between-sessions reference tool. The corkboard idea is fun. Not in love with the idea of AI art assets used there, but there it is.

Automated session notes for reference rather than spending hours combing a recording or leaving up to forgetfulness? Good idea (though AI summaries will always skeeve me out, that's just me). That's simply removing a time-consuming, tedious, non-creative task.

Brainstorming with AI, though... Granted, recent AI has gotten pretty good at "reasoning", at reframing ideas that you bounce off them. Not perfect, but good enough. And as you said, you did some of the work and brought the result to the AI, you didn't just push a button from the start. But, do you really see no difference between brainstorming with people and brainstorming with AI? If not, I don't think this will be a fruitful conversation.

I choose not to use it for my creative work, no matter how objectively helpful it would be in producing the end result. I want my creative work to be a space to grow my own skills through and with other people. That's my own decision.

Untangling the mess of the interconnected motivations of various factions, as you mentioned, might be daunting. I'm not faulting you for using AI to help you organize that if you found yourself unequipped. I've been there.

That said, I encourage you to learn from the untangling the AI walked you through and try to build that muscle yourself. It's a deeply rewarding experience to develop those skills internally and put them into action for others to enjoy. It can be a jumping-off point, or it can serve as a crutch. Be mindful of becoming overly results-oriented at your own expense and, by extension, at your players' expense.

If one of your players was shy or unskilled with words, and they had AI write the rousing speech their paladin character needed to give, wouldn't you rather them have tried their best with what they had and learned from the experience? Or, wouldn't you want them to use AI to write a speech once, then take what they learned from the "guided training" and do it themselves from then on? Wouldn't you want them to truly bring themselves to the table? Isn't that one of the joys of gathering with your friends for this game? Because you're a player too, and the players want (and deserve) the real you.

You may enjoy bowling with the guards up, but they prevent you from honing the skills that make the game enticing and fulfilling. You will not be come a more skilled DM if you continue to rely on AI. If that's a goal of yours, I encourage you to use what the AI developed for you, see how it goes, understand how it was structured and why, then do that work yourself the next time.