What's all this hussle about protagonists and antagonists? Modern literature is no longer the romantic black & white. Search the word 'protagonist' on google, and you'll eventually find the term 'focal point'.

If your 'antagonist' is the one you're focusing on, then you've misused the term antagonist.Think of all the works told from the 'dark side' perspective.

To bring in some evidence, Greek dramatists defined the protagonist as 'the first actor to engage in dialogue with the chorus', which means 'side' or 'goals' are irrelevant. A story where the good guy destroys the evildoer's plan, told from the evildoer's perspective is actually a story where the good guy is the antagonist.

So indeed, what I'd suggest is to choose the character in the focal point to be your protagonist, and the character that stands up against them to be the antagonist. You have more POV characters? Then use the terms 'deuteragonist', 'tritagonist' and so on.