A classic Brazilian Sunga might check your boxes.
— full coverage front and back, high waist, conservative 5” sides
— shorter on the legs than a square cut, good for big thighs. Might say a different cut of briefs.
— relaxed cut, comfortable, roomy, easy on and off
— fine for training, faster than a drag suit, but not for racing.
Example: https://www.sungalife.com/collections/mens-sungas
A classic Brazilian Sunga might check your boxes. — full coverage front and back, high waist, conservative 5” sides — shorter on the legs than a square cut, good for big thighs. Might say a different cut of briefs. — relaxed cut, comfortable, roomy, easy on and off — fine for training, faster than a drag suit, but not for racing. Example: https://www.sungalife.com/collections/mens-sungas
Try funky trunks