I was raised evangelical protestant in the USA, at some point attending both Seventh-day Adventist and Pentacostal churches. My mother did not consider my Catholic grandparents to be Christians, based on her belief that one cannot be saved by confession/prayer to a saint or clergy instead of directly to Christ. As many other have said, this is not the mainstream definition.
There is simply no plugin to replace that functionality. Emacs users would tell you otherwise, but you have to remember that it’s all about the curves for those Lisp folks. I think this is probably a new software worth learning even if it lacks interoperability with some of your existing toolkit.