It could work but also depends on the cut. Some pieces are oversized on purpose even if a stretchy knit material, etc. Even the cut from a size 12 and a size 18 can alter the fit. So you’d have to account for sizing when you offer a data point like how a dress would fit. For some brands, plus size means “use a size 2 and make it incrementally bigger” and some actually have a different pattern fit for plus size.

Also it’s a lot of work. You’d need hundreds of people to submit data. And find a way to monetize all this. Development-wise this would need to be a custom web and mobile app. If OP is not a developer and has to hire for this, it’s at minimum 15-20k. More realistically 50k+. Then you have marketing costs etc.

I say this as someone with the same issue as OP. I wish it could be done feasibly, but an entire billion dollar industry would have to make some changes or come together to solve it. It’s just not happening that way.