Onsen like Kinosaki onsen

Went to Kinosaki onsen, unfortunately finding rooms were not possible this time. Curious if there are any onsen towns without all the huge concrete hotels, where yukata strolling is common. I actually went to Kusatsu onsen but it was way too cold and too far away from the hotel to wear a yukata.

Was looking at visiting Shima onsen (by taking the highway bus from Tokyo) or the onsen outside if Minakami, but the later have no such "towns" I think.

Maybe finding onsen without big hotels quite hard?

Kurokawa Onsen:
https://www.japan-guide.com/e/e4575.html

Kusatsu with a more central hotel outside of winter.

Shibu Onsen:
https://www.japan-guide.com/e/e6029.html

Kurokawa Onsen is the most picture-perfect onsen village I've seen, very much lacking in concrete.

I also recommend Kurokawa; there are not many places to take a hot spring outdoors in the middle of the forest.
https://youtu.be/Xs_JXC6bhkM

But there are hot springs all over the country - just what parts of Japan are you considering going to?

Shibu onsen
Kurokawa
Shuzenji
Ginzan onsen
Nozawa onsen

For sure there are other options as well

Shima Onsen is good. You can stay at Kashiwaya Ryokan.
https://visitjapan-vegetarian.com/kashiwaya-ryokan-the-best-place-to-s...

If you plan to visit the Kansai area, can consider Arima Onsen too.
https://visitjapan-vegetarian.com/arima-onsen-kansais-best-onsen-town-...