Then you should fix your app so it can be used by color-blind users. Aside from that, you should use distinguishable background colors A, B and C specified by the system color theme. It's more likely that its designer has considered accessibility issues than that every single app developer has.

Have you looked at the set of colors that is actually defined by a theme? That is my point: I would use these colors gladly if they were there. They aren't.