So I just seen this https://www.youtube.com/watch?v=yhseQP52yIY
DHH talks about cache template results. I'm wondering if this a a thing in thymleaf. The section about cache in the documentation is pretty slim.
As I read it it's only about caching the function generated for a template file. Maybe I read it wrong.
I wrote a dialect extension at the time that allows caching of the resulting html. I hope it‘s what you looking for :)