Tbf, Koikatsu character models (such as in LiL) are at least as repetitive as Daz3D models.
In my personal opinion, I don't see a correlation between different game engines and the quality of a game. Whether a dev uses Daz3D models, Koikatsu, Honey Select, AICG, photo-tracing or hand-drawn graphics will just impact the personal visual taste of the player. There's enough good titles using either of those styles. Some of my favorite games are text only even.
The fact that so many popular games are using Daz3D models is probably because it is easier to use/edit existing models than having to create images from scratch (e.g. hand-drawn). I wouldn't even say that there is a lot less Koikatsku or HS games out there though, which are comparable in terms of effort used in character creation. AICG is also not too difficult to use, at least if doesn't have to be perfect, the high quality ones need a lot of work too though (a lot of touching up).
I also find it funny that you bring up the RPGM engine and highlight it positively. This is by far the most archaic engine still in use, probably because the sex game dev slaves in Japan keep pumping out low effort slop in that engine to this day, somehow keeping it relevant.
Tl;dr: You can't derive the quality of a game by the engine or the character creation software used (unless it's very sloppy AICG, I guess) and need to look at them individually.