There are suppliers of panties cut to fit male parts. Google "male lingerie".
So call me old fashioned but what defines male from female garments is the cut. If you cut the undergarment for a male's physique then it's not a pantie anymore, it's underwear. Lingerie is a more specific term that refers to the style of the garment and in particular what's used to make it, and that's usually silk satin fabric, lace, fishnet, or gauze, but cotton lycra and spandex are also used. stockings garters panties g strings, teddies, nighties and peignoirs I think are all the possibles oh and corset and bustier in certain cases. Men's lingerie or what is much more closely related than todays regular men's underwear was just as much a thing in the past as it is becoming now.
https://art2130araceligarcia.wordpress.com/2016/11/07/mens-underwear-1700-1870/
And this is a new line but they have made these things for men as long as they have for women.
https://www.lhommeinvisible.com/en/mens-underwear/the-couture-underwear/sheer-softness-of-lace/
This is the prototype and the women's fashions take after it, or rather the forerunners because men were the designers and sellers and promoters of women's undergarments which were designed for the male gaze, not for feminine pleasure first, and women were not allowed to be immodest and did not generally show any of their undergarment outside of the home until after the 1950's.
https://www.lovetoknow.com/life/style/history-panties
So all that to say, the male garments were cut to fit female parts as one might expect given the patriarchal focus of the 19th century, they both evolved around comfort and in some cases chastity but it wasn't until mid century that the era of mass market lingerie was upon us, and men have been wearing and designing that apparel for themselves to their own needs for just as long if not longer. Which leads me to the final point which is that the "true" or authentic panty fetishist (which is specifically only those who get sexual arousal to completition from wearing these garments) wants them to be cut for a woman as the discomfort and bad sizing are part of the fetish.
I am a nudist and I hate wearing clothes, but when I have to , I like the feel of panties. They just feel better. That's all. Does that make me fem or drag or whatever? Who the hell cares?? Labels are created by people who are plain scared of being openminded. If panties feel good, or a thong feels good, go out and get some. Or as Nudistpig wisely pointed out, find a cut that is designed for a guy, get it in the material that you enjoy, and enjoy wearing them!