Ask HN: What's the state of high level containerization?

Right now, containerization is powered by kernel features. This requires virtualization on non Linux machines and is a bit cumbersome as a result.

I have been hearing stories of the concept of "high level containerization" which promises OS-agnostic container functionality through application-level abstraction.

Some have cited "web assembly" as offering that capacity, I have heard Deno describing intent to provide such capabilities.

Are there any projects out there today that can be used for this purpose?