You just have to look at these graphs showing how quickly they have grown in prevalence in South Africa. In a month or two we will be the same.

BA.4 and BA.5 are more like BA.2 than BA.1 (BA.3 seems to have disappeared almost). The both have the mutation of concern L452R that was found in delta to make it more infectious and possibly dangerous. Delta was about 10 times more dangerous than Omicron. There is still a #deltacron recombinant child floating around last I looked.