This is what makes me mad; it's as though they didn't care or lived in a naïve world.
The Jews, Christians, Muslims, Dharmics, Daoists, Confucians, Zoroastrians and others have their holy writings. These are compounded by great works like the Talmud, Church Fathers, Hadith, and other such traditions.
And we have some longbarrows.
If they would have been allowed to pass on their oral traditions some of that wisdom would still be around, writing is not necessary.
But there is also a lot of spiritual wisdom left from the indigenous populations of Europe by reading through the myths, folklore/takes, and of the various Gods/Goddesses and pantheons. We just have to look harder for that info and do a lot more inner work with it. It's not directly spelled out with a "holy writing" which isn't really a bad thing either.