OP, I’m a Christian (I’m going to four services this Christmas Eve/Christmas Day), and I get where you’re coming from. I’m now a moderate Christian, which doesn’t mean I hold my beliefs any less or believe the essentials of the faith to be any less true, just that they are broader and more compassionate beliefs.
But I grew up with Christian fundamentalist parents and it really scarred me. Growing up with the constant threat of hell for normal childhood naughtiness is horrible and terrifying, as is having said naughtiness or simply doing something they disagreed with put down to satanic influence. Perhaps the worst thing though was feeling completely isolated from the other kids at school because I truly believed they were all going to hell and it was my job to convert them.
I spent a lot of my 20s feeling very damaged by this upbringing, very angry as you describe, and was a vehement atheist for a while. I’ll spare you the rest of my journey, but the anger did pass eventually. I have now come to the realisation that my parents are very damaged people who used fundamentalist religion as a crutch for some difficult personality issues and traumatic life events. Sadly the crutch has failed them in old age and they are now alone, bitter, and nasty. They no longer even go to church, but they are just the same as ever they were or worse.
I can certainly understand that being around your parents’ Christianity might be difficult or even traumatising for you if you had a particularly bad dose of it growing up. I would echo what others say about taking breaks, deep breath and count to 10, and so on. I think the way through this for you, with therapy or whatever else helps, will eventually be to find your own spiritual path, or belief structure and way of making meaning in the world, whatever that looks like, which might well not be religious.
I can understand and identify with the sense of having your world and identity overturned when you realise your parents’ worldview is bonkers and harmful. Now you have the chance to build your own, which is exciting as well as difficult and sometimes painful. I wish you well, and happy Christmas.