does anyone know their sub genders?

Is this alpha x alpha or alpha x omega, or maybe even alpha x beta? Im a bit confused, maybe it's lost in translation but from the way they speak it almost seems like theyre both betas? which I know that cant be the case.. he did ask tsubaki if hes ever been in heat and he replied that hes never been around omegas in heat? maybe its something im misunderstanding lol is this a late presentation story where the bottom becomes an omega? totally lost