https://github.com/clojure/clojure-clr/wiki/Getting-started
It looks like the 1.11.0 beta has a build for .NET 6.0. Very likely, when it is released, .NET 6.0 will be supported.
https://sourceforge.net/projects/clojureclr/files/
https://groups.google.com/g/clojure-clr/c/ysQFz73K0MU