After years of lurking, I made an account to reply to this
"image-manifest=true" was the magic parameter that I needed to make this work with a non-DockerHub registry (Artifactory). I spent a lot of time fighting this, and non-obvious error messages. Thank you!!
We use a multi-stage build for a DevContainer environment, and the final image is quite large (for various reasons), so a better caching strategy really helps in our use case (smaller incremental image updates, smaller downloads for developers, less storage in the repository, etc)