I don't care a lot about this...
>Kami verneration was already part of Japanese culture for centuries
Tengrism is also teh rly ancient (3300BC is certain, there are signs of 4000BC and older), and I think forms of "nature=god" was simply an accepted fact among Asians as they were evolving enough to form languages.
>There were local shrines and cults everywhere with most attached to Buddhist temples
Turks were nomads, where the most complex buildings were yurt tents. By the time Oghuz Turks reached Anatolia they were already converted to Islam, maybe other Turks or Mongols have more traces of pre-Islamic culture
>Tengrism is completely artifical

>Its what historians call an invented tradition. There is no connection between modern Tengrism and what a Turkish nomad might have believed 2,000 years ago
Abrahamic religions are pretty unforgiving for other religions, but I listed above how it's not completely unrelated. Another thing to add, mosques here have crescent things on top, unlike other countries
Also what do you mean by "modern Tengrism"? Do you realize there are Turks who never converted to Islam?
This is I think a Kyrgyz https://www.youtube.com/watch?v=W5c_G24ImSw
If you care about it, this seems to be a Turkish guy visiting Yakut to document Tengriists https://www.youtube.com/watch?v=ENdrMDWQsvs
>The word Tengri or Tankari doesn't even refer to a seperate deity, its just a generic name for God used in Chaghtay Turkish as a synonym for Allah
Tengri (now "Tanrı" in modern Turkish) means god. Köktengri (now Gök Tanrı) means Sky God, the name of the "deity" (though it's rly just the sky, per pantheism).

>An outsider might look at Afghan villagers appeasing mountain spirits and see it as preserving some pre-Islamic belief, but those villagers don't see it that way
This is true, you just can't expect any common villager to know why they are doing what they are doing. It was this way before Islam/Buddhism etc took over too. People simply do stuff because their parents did
>Half of those "pre-Islamic" things you've listed are just mundane cultural variations not even distinct rituals linked to beliefs
You can't know that. And even if it's that way, mundane cultural stuff made up details of old religions. It's only a recent thing that culture and religion are apart. As for Tengrism, there were some other gods I don't know how much of the population knew about, but old Japanese people probably didn't care to believe Shinto deities as closely either (maybe unless being settled helped to make up more gods?)