I have read that we cannot change name(s) of the god\pantheon of your new custom faith. I have no idea how hard that would be to get it to work, but this is a really important feature, at least for me.
I may be mistaken and this is already in CK3, but if it is not, it is something I would consider to be important.
I may be mistaken and this is already in CK3, but if it is not, it is something I would consider to be important.