being sincere no one knows! well at least it hasn't been explained yet, it wasn't until recently that the members learned how it was pronounced
if you are curious about them they are the successor group of "EMPiRE", EMPiRE were pretty popular and were doing really well, all their albums / singles debuted at #1 in Japanese digital charts, they did multiple OP and ED songs for the Animes of "Fairy Tail", "Black Clover", "High Rise Invasion", in early 2022 they were wrapping up their arena tour which was bringing on average over a thousand fans per concert
unfortunately not much later they announced their sudden disbandment without any prior notice, during their final concert they announced a successor group "ExWHYZ" with all the members of EMPiRE but under a different label (they were signed to Avex before and now to EMI RECORDS which is a larger label) ExWHYZ started activities in November of last year, so just a few months ago
worth mention that they actually are two different groups even if they still have the same members, but all songs are different, the image of the group, etc, they just held a concert in "zepp divercity" (capacity about 2,000), they have a few more arena dates before their Budokan concert which a pretty large venue, basically a stadium, is almost two times larger than the capacity of their largest concert
also they are pretty good!
sorry for the wall of text, i know you asked for what their name means, don't have an answer right now but we probably are going to find out evetually
