It sounds like she knows more about the arrival of Wave 4 than she's letting on, too. We know only 2 weeks separate the cutoff date for their audition but even I would appreciate a January release.
At the very least, I hope Wave 4 is the last for a while so the existing members can intake more fans. Then again, I feel the men are going to attract a completely different audience and Waves 1-3 will be pretty untouched.
Anecdotally speaking Niji guys and girls tend to attract
mostly different audiences. There is obviously some overlap, and the bulk of the audience for both is mostly male (contrary to some often-repeated, unfounded claims), but the Nijisanji JP and ID fans I know tend to either mostly watch and focus on either the girls or the guys.
I think the male wave is worth getting out because they'll be the first agency with any degree of significant name recognition to debut male EN vtubers. Even the smaller agencies like Prism, Tsunderia, and Phase Connect have stuck with girls. It is a gamble, no doubt, but the floor for their popularity is still likely to be much higher than the current audience male EN indies get, making joining Niji well worth a shot for male indies (even if they get half the views of the girls that would still be
many times more than male EN indies currently get). I often hear EN vtube fans say that they would be interested in watching male vtubers but don't know "how to find them" because they're all indies.
If they end up doing better than expected, it'll be something that sets the branch apart. They've been having a lot of success with guys in the JP branch this past year (the top guys regularly out-earn the top Niji girls and even rival top Hololive members in terms of superchats from time to time) and Ha Yun from the latest KR wave has had better growth than his female genmates.
NijiEN will probably never match HoloEN in this market, but if they can establish themselves as a solid second or third it's worth the investment for them. I do think that they should hold off on female waves for a while, probably till mid-2022 or so IMO.