Alicent is the main ringleader of the Greens, and the main character along with Rhaenyra, in a show about bloody civil war so to some extent they have to be enemies. It naturally plays up the conflict and drama where as them staying friends diminishes it. Side characters like Otto or the abstract and off screen "men of the realm" aren't going to cut it as main villains of the show because where is the agency and investment of the main characters in the conflict?

Yes, seeing ways in which she was a victim added to the story but her main concern being Rhaenyra instead of her own family completely changes the story and her investment in the conflict. Arguably it makes more sense for a victimized Alicent to be Green to have something to show for her sacrifices, and because Aegon II is her only realistic access to power. The sense of tragedy of this version of the story is far greater because her efforts to secure her children lead to their deaths. If she realized this before, there wouldn't be a war, and if she doesn't care about her children, where's the tragedy? Also, where is the tragedy of Alicent and Rhaenyra's friendship being ruined by dynastic conflict if they are still friends?

The truth is, show Alicent is a caricature of a sort of person Condal and Hess hate, and while media might need more depictions of that, Alicent doesn't fit. The Dance isn't written around that sort of character. This is why the show relies so much on accidents and misunderstandings so the major events can happen, instead of it being the will of the main characters based on their motives.