As someone who grew up in the catholic school system in the US, I was always told the church could trace the papacy and Church’s founding all the way back to the apostle peter, however, I recently discovered this claim may be more dubious than I even originally expected. Would it be more accurate from a secular perspective to say that St. Paul founded the church? Thanks.
You may want to cross post this question to /r/AskBibleScholars or /r/AcademicBiblical , they may be able to assists with directing you towards historical materials regarding the early Christian communities.
I think there's a lot to be said though, and AskHistorians has its own unique community, so I hope for many answers on this sub too.