I bought Jockey String Bikini underwear out of curiosity and found them to be the most comfortable underwear ever. https://www.jockey.com/catalog/product/jockey-mens-elance-string-bikini-3-pack?color=5520

Amazon also has several: https://www.amazon.com/dp/B0BC16WKSQ/?coliid=I3O7S3BITGMOI7&colid=1F8OD9AQR2WNT&psc=1&ref_=lv_ov_lig_dp_it