i heard male omegas impregnating themselves is up to interpretation, but some say that their sperm is way too weak when their heat cycle is coming up and need beta/alpha sperm to get preggo idunno
same goes w female alphas, i heard their hormones could be unstable to impregnate themselves
but overall im not sure LOLL
now this is my expertise (I went on a whole rabbit hole regarding these omegaverse, nameverse stuff back then soo agshdjdj) ,, these are entirely up to the author on how they'd present their omegaverse rules,, so technically anything can be canon. If that's how you choose to present it, then yea they could.
realistically would a male omega or an alpha female be able to get themselves pregnant