There are many Christians who are “not the best Christians” you’ve ever seen. That’s kind of the point.
If people have become loyal to their Christian God and are serious about trying to become better people than they were before they found Christ... as flawed as anyone might be, that’s Christian enough for me. Can Christians become misguided? Yes. Can Christians sometimes give in to the darker sides of human nature? Yes. Can certain Christians maybe embrace their religion in a way that I really do not approve of? Yes, but all these things are irrelevant.
While I do expect some measure of allegiance to their religious culture, if they have embraced Christianity to try and become better people than they were, and openly worship the Abrahamic God, I see no reason not to consider them Christian. I might not always agree with their perspectives on certain issues but I have massive respect for their religion and appreciation for what Christians have done to the world around me.