With regards to the entire trend of so-called “sexualization” of female characters in art, there is a simple explanation for that. Straight male artists, myself included, like drawing pictures of hot women. Always have, always will. This predates patriarchy as a social institution by thousands upon thousands of years. And it’s not an impulse exclusive to straight males either, as a casual glance at the romance section in most bookstores will show you. Nothing more to it than good ol’ emotions inspiring art.
And it’s not necessarily sexism either. There is a world of difference between sexual desire inspiring art and restricting one sex’s opportunities or denying their humanity. Even so-called “objectification” is more about LIMITING one sex to a certain role (namely tool of reproduction) than simply appreciating their sex appeal. The female characters you’re complaining about may have been designed with sex appeal in mind (although in many cultures around the world, showing more skin is a daily fact of life), but they’re hardly barefoot-and-pregnant types with no agency.
On the other hand, you do raise a valid point about double standards in how men and women in this kind of art are represented, but I would chalk that up to male artists predominating this genre. Part of that might have more to do with more men than women being interested in art of this genre, but I wouldn’t rule out gender discrimination in hiring artists either.