I thought Asatru was actually called Germanic in Ck2 once they added Charlemagne.
If you look at the ancestry of various anglo saxon, old saxon and gothic characters, they are "Asatru".

Please add Shia and Sunni again it the most important for me

ironman?

I like the changes you have made. For historical accuracy and to remove the froofy CK3 snowflake religion names that have nothing to do with history (Seriously, Asatru?), I would suggest considering the following:

Germanic
Finnic
Ulgric
Baltic
Slavic
Magyar

As a student of religion and history, to me this is what makes sense.

Would also suggest removing Insular Christianity.

Removed Muslim changes as after reaserch, ye it doesnt make sense in CK3.
I could merge all the schools into blanket faith but that would alter gameplay which is against the purpose of this mod.
Therefore I have decided to leave the CK3 names for Muwalladism and such.
Also if it wasn't obvious already I know almost nothing about Islam so sorry for any confusion caused.

I would also suggest to change Shia-Muwalladism. That's pretty much a mixed ethnic group following Sunni branch.

I don't think muwalladism is Shia, it's a part of the Sunni school

Never understood the nuanced change anyway. Just makes people confused about obvious religions