The kpop community, be it international or Korean, has always been largely dominated by female fans, right? One of the main points you're missing, which could be related to your #1 argument, is that those female fans no longer want to support problematic male idols. Although yes, female idols also get involved in scandals, male idol-related scandals tend to be more related to violence or, even, violence against women. I've seen this going around on k-communities and twitter and people are just scared of stanning potential predators, for the lack of a better word.
Aditionally, ggs (well, at least ggs from the big 4) have been releasing 'empowering' music that is more appealing to the female audience whose lyrics resonate with them. That also explains why Miley Cyrus' Flowers or Shakira's most recent hit have also gotten extremely popular. Songs about empowerment or standing up for yourself attract a lot of interest.
