Giganta and Angle Man are primarily Wonder Woman foes, for example, but they're usually in some other book.
I'll totally take your word on it, but that sounds crazy to me.
Sometimes writers like to use the fact that these characters exist in the same universe, and pull other people's villains in.
That's fine, and I've certainly seen it before. But I think it definitely reduces the conflict for me, and I think it would--and this is a completely personal opinion, but stories feel more interesting to me when it's not somebody else's villain the protagonist is fighting. Batverse is different, because they're all so always up in each other's business. But WW crossing over to Batverse in her own book, especially with no interaction from the heroes of that universe, feels odd to me.