Dude, 4th gen was the only time girl groups constantly surpassed BGs on charts as far as K-Pop. It sadly is one of those constant things that seems to always come back, even if they were all somehow bland boy groups, they will likely become more popular and successful than female artists. The culture still leans toward excusing men's bleh behaviors, while crucifying women for reading a book or wearing "ugly" clothes, while also yelling at them if they chose to not wear baggy clothes.
Also, when it comes to charts, they are not based off of who is actually listening to a group and invested in them as artists either usually. It is based off who spam streams the most and buys too many copies of albums that they do not need, just so they can meet their faves. Who traditionally does that, boy group fans. Female girl group fans also buy a lot of albums but they tend to not buy mass amounts, and the ones who do, then sell them sealed to other fellow fans for half or more off the price. Sadly, in recent years there have been numerous cases of NCT fans specifically, buying mass amounts of albums and instead of reselling the ones they do not use, they toss them in the dumpster .
Edit: Before someone comes for me, I have an NCT shelf at home, but I just only buy items I actually want and will enjoy. Not excessive amounts of them, only to throw them away. NCTzens especially are honestly needing to get better at buying the small cardboard box with photocards like Pocas instead of contributing constantly to more and more pollution and waste. If you do not actually collect the music itself that is honestly better for you, and for the rest of us who hate seeing albums tossed to the trash constantly and not even trying to give them to a fellow fan who might want them. There has literally been girls at Twice concerts and NCT shows who save and then give away extra copies to fellow fans who may not have a specific album that they have extras of. So if you are insistent in buying too many full sized copies, maybe try gifting them to someone else who also likes the groups.