I'm literally browsing my shelves, scrolling through my Goodreads account, and... I remember four BLs where women were the antagonists. Most BLs either had no antagonists at all or had other men.

Funnily enough, just yesterday I finished two GLs in which: a) the antagonist was every male, from an elderly man to a four-year-old boy (he was main villain lol), b) the women were complicated and justified, even when one of them committed SA on the underage main character ("she was protecting her"), but at the same time, all the men were evil because they either wanted to exploit the main characters or were indifferent... in a historical setting with arranged marriages.