I have both Rapha & Levis Commuter jeans and both are very good fits.
The Levis are a “looser” fit and slim waist even if they are of the skinny type, ok slim rather than skinny. Also you can’t see the seat pad in them and they only have 1 extra layer of denim in that region anyhoo’s so it makes no differance.
The Rapha jeans don’t have extra padding nor layers, they’re just a different treated denim with a bit of stretch. They are not the same fit as the Levis, Raphas are slim and thats it, they stretch well but from what you say you’ll probably not fit in them,
Of the two models, I prefer Rapha but then they fit me, thats why I like them. I’ve been using them for 3 years now and have 3 pairs.
Never tried any other cycling branded jeans.