Woah. This became the guidebook.

Sure, but does the rest of the world?

You can host your own with harbor, and set up replication per repo (pull upstream tags) If you need a commercial product/support you can use MSR v4.

Harbor can install on any K8s cluster using helm, with just a couple of dependencies (cert-manager, postgres op, redis-op) Replication stuff you can easily add.

I have some no-warranty terraform I could share if there is some interest.

You can also host your own with harbor (or MSR v4 if you want a commercial product.) You can set them up to replicate upstream.