The formula for growth remains unchanged.
Biblically accurate + culturally relevant = growth.
Change either or both and you sharing or die.
The Celtic way of evangelism included both - before Rome destroyed it.
The pagan tribes in Ireland were evangelized and converted in short order.
Later the Celtic Christians used the same method to evangelize the Roman Empire after the invasion by pagans.
Later, this gain was destroyed again by Rome.
And so it does even today.
The “Celtic Christians” of Ireland just voted in a majority, something like 70%, for sodomite pseudo-marriage.