Calm traditional place in autumn season

I am planning to go to Japan at the second half of November and beginning of December (preliminary) and I would like to stay in as quiteful place as possible and in a traditional nature environment with beautiful autumn colours. I am searching in temple lodging but it is difficult to choose. I want to avoid mass tourism and many foreign tourists as I saw in Koyasan. Have you any suggestions?

For temple stay consider the serene Eihei-ji in Fukui Prefecture.
https://daihonzan-eiheiji.com/en/guide-sanzen.html

Thank you very much for your nice suggestion. If I understood it right you, as a visitor, can't live in the temple, but in a modern hotell, can you? It looks really nice temple, but I am afraid there are many tourists, almost one million per year I have read...

Fukui is not Koyasan. It has the second smallest number of foreign tourists stay in the prefecture out of the 40 odd prefectures in Japan. As such - there will be some western tourists but not hundreds at a time such as what you might see in Kyoto

https://statistics.jnto.go.jp/en/graph/#graph--inbound--prefecture--ranking

From what I am reading from the website provided - you stay in the temple such as what you do in Koyasan but it's much more involved than the more touristy temples.

The temple mentioned can get quite busy, but this will probably be more with Japanese tourists. Staying AT THE TEMPLE will significantly change how you see the location - as you will be there before and after it's open to the public. You might also be able to access locations in the temple which are away from the public - but others will know more

Thank you very much for your explanation.