I kind of second this. It’s an idea that I’ve been floating for a while myself - a more mature Sims-like.
The real difficulty would be programming it. Part of the reason Sims 2 and 3 were so notoriously buggy was because of how many interactions and scenarios were planned into them.
If this were attempted, it’d have to be to the scope of Sims 1, where you were limited to a single lot, and no lineages.
But for now, someone on here is working on something that’s pretty close:
Unreal Bellyful Life: A 3D WG Stuffing Inflation Sandbox [v 0.3] (2025 Update!)
Granted, you’re limited to only female inflation, if you’re not into that, but it’s a start.