I don't comment that often, but I have to say that I really like both your game idea and your approach to the development process. For example, I appreciate how you mentioned that you don't feel right about monetizing the game before providing at least a good demo, and how realistic you are about the challenges.
In my opinion, the first impression is the biggest factor in making people interested in your project. Please don't rush the demo and take your time within reasonable limits, of course, because it's easy to fall into the trap of never releasing it.
I've recently become a software engineer professionally, and working in big tech is much less exciting than I expected but at least I have a lot of spare time at work while I work my remote days. That's why I started learning Unreal Engine as a hobby, and I'm thinking about creating a game that goes beyond just a Ren'Py visual novel, incorporating actual gameplay.
I've played most of the more popular games that include gameplay, and I can confidently say that the bar is really low. Most of these games are painful to play, at best decent, and rely heavily on outsourced art, which is usually quite good. These games are basically galleries with boring and often grindy gameplay, designed primarily to unlock scenes. In my opinion, the adult content should be integrated into the gameplay in some meaningful way, rather than being tacked onto a poorly made SFW game that rewards you with NSFW scenes.
I mention this because I like your project and have high hopes that it won't end up like the games I described above, as it currently shows great potential.