AULA keyboard differences?

I’m looking to buy my first mechanical keyboard, primarily for gaming and tinkering with customizing switches/keycaps.

I was first looking into keychron but was turned away because of their quality control issues and lack of customer service.

Anyways, I’m pretty much looking at getting an EPOMAKER x AULA keyboard…

What’s the difference between:

- AULA F75

- AULA F75 PRO

- AULA F75 MAX

- AULA S75 PRO

And any other AULA 75% keyboards…

Any help is appreciated!