I basically boycott patreon, so I can't really message there.
For merch, I'd absolutely wear a shirt with a broken collar that says "Spending time in church broke my rebellion"
or perhaps a picture of some phallic shaped thing with angel wings or something to make it look kinda not-intentional and something like "True prayer begins by being on your knees"
Although if you want to have stuff less linked to the religious stuff which can be a headache all on its own, there is also:
Gym themed:
"Squats is my source of protein"
"Exercising taught me how to breath through my nose"
Casual:
"Why do people keep asking if my Landlady is my mom?"
*picture of a collar* "Looking for adoption"