Back when I was playing Skyrim I used a few mods in conjunction with one another that gave a really realistic experience. One was a full “survival” suite of mods including stuff like Frostfall, Campfires and (most importantly) a needs mod - I think it was either something like iNeeds. This made it so that I had to keep food and drink on me, eat regularly and often spend lots of time in Inns whenever I got to towns to compensate for going out on the road.
The next mod was Being Female, which was a super intricate (but somewhat hard to get working) mod that added pregnancy, a full menstrual cycle and birth control. The mod actually changed your body if you had CBB installed, so you’d be able to see your growth over time. Also, when you were in later stages of pregnancy, you would (realistically) be a lot slower on your feet and need to rest more, leading to lots of sedentary moments of snacking during that third trimester.
The last mod I used was called Pork Up (iirc, and also WeightMorphs) which was a weight gain mod. It had several triggers for what would make you gain weight, but the one I used was just eating food. Different foods have different caloric values which would lead to more or less weight gain, and activities like running and jumping would burn calories, leading to weight loss. Like Being Female, it can change your body if you have CBB installed.
The culmination of all three of these was a really niche but super hot fetish for me, with a fit and muscular adventurer finishing her story arc before settling down and getting pudgy during peacetime. I just love that idea of the badass hero of legend who fought and killed the king of dragons slowly transitions into domestic life where her waistline loses the battle to sweetrolls. It’s a long, LONG playthrough to get the full experience but the realistic, slow burn of it all was thoroughly worth it for me.
I almost certainly got the names of some of the mods wrong but if you’re looking to build a complete WG mod then those I listed (and how they synergize together) would probably a great place to start when getting the full scope of the concept together. And yeah, as others have stated it would be great to have one mod that was really targeted WG cuz trying to get 10+ mods to all play nicely together is a headache, lol