Hi! I can't see the horse gender with or without the hwyla mod, and when I try to generate colored horses, I always get the same horse cape and size.

I'm in 1.16.3

Have you enabled genders in the config? If you're in multiplayer, are genders enabled on both the server and your client?

It's a server hosted by me. I changed the genders thing and the genders are not seen

It sounds like the genders are enabled on the server but not the client. I'd recommend checking the config on the client side and enabling genders there as well.