Just give the non-humans different cultures.
In my setting brass dwarfs, stone dwarfs,gold dwarrfs amd so on are pretty different from each other - they have their own customs and regional appereance.
Also one thing that is underated: Human subspecies.
For example, do you known that HOBBITS are humans in Tolkien? I included in my setting different sorts of humans, like humans with long limbs and frog legs that live in marshes - or humans with horns based on ancient iberians.
But ANOTHER point that I would like to make: playing "only humans" game to "preserve exoticism" is possible but also a bit close minded. Have you tried playing a game where EVERY PLAYER MUST BE A NON HUMAN OF THE SAME RACE? Like an all dwarf party exploring dwarf ruins, an all elf party protecting their woods and so on.
I did, and it was fucking fantastic to get the players to enter in a typicaly non-human mindset, "dwarf" and "elf" become the "default", and ghumans become exotic. During the all elf game, the only time a human showed up was SURREAL and exotic and ended up being a huge surprise for everyone.