@serenity_1 - I understand that type of fear all too well!
And I see where you're coming from. Here's the thing, though: you don't have to use OCD as an excuse in the first place. Exposure therapy is also not unique to OCD. Whether or not you have OCD, it's still a good idea to do things you want to do despite thoughts or fears that are holding you back.
ERP therapy, the current gold standard for OCD treatment, is a useful tool to have regardless of the reason you're afraid to do something. It's just a form of exposure therapy that is specifically tailored to OCD in terms of the terminology it uses. But the underlying technique is useful regardless of where the fear is coming from.
You have it exactly right: what you want to do is actively "show your brain" that the thoughts and the anxiety are not things you need to "get rid of" in order to live a normal life.
What you're describing, which is essentially the fear of damnation due to following the "wrong" religion, is extremely common. After all, there are thousands of religions out there, many of which have their own concept of "hell" and ways to end up there. It's perfectly understandable to feel uncomfortable about that.
But whether you have OCD or not, the only way to not allow this fear to take over your life is to prove to yourself that ruminating about it, or avoiding doing things you want to do, is not making you any "safer." In fact, it's only making the fear worse. Every time you do something (research, ruminate, avoid, etc) in hopes to get rid of this fear, the thoughts about it becoming increasingly distressing. Again, this is true whether you have OCD or not. It's just how the human brain works.
In terms of OCD exaggerating things and causing excessive doubt, I would say that's pretty accurate. It's nicknamed the "doubting disorder" for a reason. It's been shown that people with OCD have overactive circuits in the brain that are responsible for "error detection." In other words, the brains of people with OCD are literally wired in a way to perceive even the tiniest bit of doubt or uncertainty as a legitimate threat. Since being 100% certain about anything is basically impossible, this is what leads to bizarre rituals and compulsions that make very little sense; people with OCD develop all sorts of strange and unproductive habits just to feel any ounce of control and certainty that they can.
Regardless, my advice still stands: you don't have to use OCD as an "excuse." When you practice something like ERP, you aren't doing it "because you have OCD," you're doing it because you no longer want the thoughts or fear to completely control your life. After all, even if you sit in a room and do nothing your entire life, you're still going to be breaking the rules of some religion somewhere.
Please refer to any of the links that Nica left for more info on things like ERP. And remember that it's all useful info regardless of whether or not you qualify for the disorder.
Hope this helps!