I recently discovered trunks with a boxer brief style liner. Sort of like spandex material I guess? Found a pair at target https://www.target.com/p/men-39-s-7-34-stripe-swim-trunk-with-boxer-brief-liner-goodfellow-38-co-8482-xs/-/A-84027112 but also a brand called Milankerr on Amazon MILANKERR Compression Shorts for... https://www.amazon.com/dp/B08VRCV3D2?ref=ppx_pop_mob_ap_share.

Cannot recommend highly enough. I was always getting chafed but wore these all day on recent vacation. Even played volleyball in them. Heavenly!