It has that kind of feel as if it's made in codex.

It takes more like 10 seconds. For a large range of height and weight inputs crossed with all option combinations, you could precompute ~10M measurements and return results basically instantly.

I'm guessing the writing is AI-assisted (there's no fluidity and it has some weirdly placed phrases) but I see they're in Poland and likely not English-language first?

Well sorry no, because already the torso to leg length ratio is covered by none of their question. (and yes, they list it as a limitation)

How big are the pockets and is it sex determined?

ai;dr

MLP trained on 8 questions achieves ~0.3cm height error, ~0.3kg weight error, and ~3-4cm for bust/waist/hips measurements.

https://www.mdpi.com/1424-8220/22/5/1885 + some hacking => "we want to productize this"