It’s a little different than a baddie like Black Panther’s Killmonger.
So, by the time Janet van Dyne returns with quantum healing powers, I was fully on Team Ghost/Foster.
Left to her own devices, she could be a bigger baddie than Killmonger, but there’s also the idea that her character still could see the light and be a heroine.
She nearly derails, threatening to go after Scott Lang’s kid, but she has someone who genuinely cares for her, and Bill Foster talks her down off of the ledge.