I think there's overlap in the complaints you see for RPGM, HTML, QSP or other sandbox titles. It sucks to hit dead ends (Like adding a club to the minimap and then getting a prompt 'coming in future update') and just generally to feel you're wasting time. Grind is vaguely tied in with that. I don't mind working for something, but then the working itself has to be somewhat rewarding, not something I want to get over asap.
And that's why I won't even touch RPGM games, I've tried quite a few, even the highly rated ones, and I just hate walking between locations if there's nothing to be found on the path. That feels more like padding than gameplay. And if you're delaying me from seeing an erotic scene, it best be for a better reason than 'you have to arrow keys your way to the other side of town'. Don't need instant gratification, I don't expect a widow to go from cup of coffee to anal in a minute. But when the anal IS on the table, then having to spend extra time just walking over? That doesn't feel rewarding or fun.
Anyway, just my 2 cents, Unity makes more sense to me. And I think if you do make your first title on RPGM to 'see the feedback' I imagine the loudest feedback will relate to 'why RPGM though?' and assuming it's otherwise a great game, missing stars in reviews are probably going to be linked to 'unneeded grind/so much walking'.
That said, while I've played a lot of games here, what you are looking to develop isn't exactly my niche, so what I just predicted to happen is more based on what I've generally seen across F95, not specifically in the genre you seem to plan to take part in.
Whatever direction you take though, it seems you will be investing a lot of time and money and mental energy, which I admire. So I can't do anything but wish the very best for your project! It doesn't look like it's for me, but I'm but 1 person of millions so please don't take my hesitancy to heart.