For the love of god, avoid Temu. They have cool looking clothes but they’re awful for the heat and they fall apart after a few washes.
It might be a boring answer but Lulu does guys as well. They’re the go-to for a lot of women and guys have less choice, this might be the only real brand made for it.
And they have shorts:
I know some guys in my studio just wear whatever Nikes they have lying around but if he wants to take it seriously, this is probably the best quality. This and a good mat will last him for years.