Please take into consideration that there is a need for nested docker repos (one additional level is enough like GitLab has per project). The overall ECR/Azure/GitHub registry stuff is so crazily limited it’s borderline unusable: you have to pop up projects/registries just to have a different image name, and tags are limited to 128 chars, within [A-Za-z0-9-_] (so, no slash), so you need to spawn repos like crazy (which means different creds or setup or project settings) and/or suffer unreadable mangled tag names.
FWIW Google Container Registry (GCR) allows arbitrarily nested paths.
Part of the difficulty though is that the Docker Registry V2 API more or less assumes the two-level namespacing. Technically GCR might be considered to be in violation of the spec. I just wish everyone was.
