Wait can all betas and alphas get pregnant in all Omegaverse? *males*

Well for manga, there's some of them could be possible

For manhwa, some of them impossible

Depends on the author. In this one, it seems they can. But there are many others where only omegas and beta women can get pregnant.

Okusama wa alpha is another one where alphas can get pregnant:
https://www.mangago.me/read-manga/okusama_ha_alpha/

depends on the writer, they can change some of parts of the whole Omegaverse concept to have their own kind of verse. there is an explanation somewhere from the writer herself.
i prefer this kind of verse. anyone can get pregnant.