Is this the sort of thing you're looking for? - white shorts, especially the middle bottom of the 3x3 display (at time of this posting)
https://www.shinyshortzryan.com/stor...all-sizes.html
Also, these Adidas unlined shorts (note the style - retro, but with neither the Sprinter overlapping side flap, nor the Beckenbauer side notch) become really quite see-through when wet, especiailly where the material clings to the skin. I own a pair and swim in threm at my gym pool occasionally, and I would not be comfortable doing so if I didn't have a towel right next to the edge of the pool when I get out. In fact, even when dry, they are somewhat see-through. When wearing coloured (but quite pale colour) briefs underneath, it is clear that I am doing so. These shorts have been flowing onto UK ebay for months if not years from various sellers, I suppose a large cache must have come onto the market to wholesalers a while back.
https://www.ebay.co.uk/itm/Adidas-Re...AOSwozpcq4c E
Edited to add second suggestion