Tough situation. I am going through something similar with my family. It sucks when you can't identify with the people you're supposed to be close to.
I can only give you this piece of advice: Stay true to yourself. Don't fake it but don't get sucked into those conversations that will lead to nowhere. It sounds like your folks are deeply invested in the Christian lifestyle so there's really nothing you can do to be better understood/accepted. It's a hopeless feeling for sure, but I'm telling ya some gaps between people are just too wide. Do what you can to remain cordial, but keep the relationship limited. You don't want to get to the point where they associate your presence with feelings of grief and frustration.
I can only give you this piece of advice: Stay true to yourself. Don't fake it but don't get sucked into those conversations that will lead to nowhere. It sounds like your folks are deeply invested in the Christian lifestyle so there's really nothing you can do to be better understood/accepted. It's a hopeless feeling for sure, but I'm telling ya some gaps between people are just too wide. Do what you can to remain cordial, but keep the relationship limited. You don't want to get to the point where they associate your presence with feelings of grief and frustration.