I'm also interested in this, I can't seem to find any COM libraries for kotlin native at all. Nor any blog posts.
I'm thinking I'll probably have to write a winmd parser and generate some c headers based on the metadata, use c-interop to get kotlin code and then use that to do com stuff. But it's a lot of work for something that feels like it should be part of the platform libraries.
A big problem with windows it's lots of the modern stuff is c++ based with no C ABI.