@Damianus
Step 1: Find out where your computer stores vanilla CK3 files.
Step 2: Find out where your computer stores files for subbed mods.
Step 3: Find out where you put the mods you make yourself.
From there, you use steps 1 and 2 to learn how to do various things. Then step 3 to actually put it into action. It's one of those "the basic things are kinda hard to learn, but once you know them it's easy, and everything else is semi-easy."
There's a CK3 modding discord as well, great info there.

It seems i did find a way to prevent this, i went back to let the ai select a non zealous pope, he will be less likely to start one. I literally have no idea how to even begin modding, i would have to watch tutorials.

@Damianus
I don't play ck3 anymore, thus no new mods or updates from me, HOWEVER:
Anyone who wants to is free to make their own update of this mod.
I remember that mod took me less than an hour to make, and I didn't really have any modding experience at the time. Should either be a super easy job for an experienced modder, or a good learning exercise for someone who's looking to get into it.

I wish this mod was still running. It's so stupid only kings and emperors can make holy orders. I don't want to deal with a dutch knights templar order because the pope is dutch. I wan't to make it as a French person but i can't be HRE emperor soon enough before the pope founds it.

No need to blasphemy.

AI can use. Also, it increases the limit on how many there can be of a particular religion before AI of that religion stop making more of their own.
...
this mod hasn't been updated in a long time, and I won't update it cos I don't mod anymore, so beware of that... but it probably still works exactly as it's meant to

Maybe a stupid question but is this Player only? Or an the AI use?

Very cool.