Is ultimate victory as pagan WRE even possible?

I've been setting up a campaign where I tried to do everything to see if it was possible to get the patriarchal see but then convert to paganism, but kind of got caught by surprise to see that religious influence effects of the building chain in rome ended up being applied faction-wide (despite not being stated as such in the building card)

So... Without mods I guess it's definitely not possible, unless you'd somehow get another faction to convert to Latin christianity, have them capture a pentarchy see site, and build the max building to for you to then capture, since there is no chance in hell to keep that 35% paganism until the final building is completed then.

Well, at least I now know that it does make sense in the beginning of a WRE campaign to demolish any church EXCEPT in Rome, as then you should have an easy time keeping religious influence faction-wide, and not be crippled by the upkeep...

Edit: Oh, wait... it's just that the religion buff via tech works on every region of each province, instead of just applying once per province, I think? So with any fully owned province it is +3 +3 +3 = +9 instead of a +3 = +3 as suggested by the tech effects.