The first time using the Google Cloud Run, some months ago, I was able to use UDP and TCP port, but now it seems it's only using TCP on the latest release (v1). The UDP port is only supported with Google Cloud Run Anthos but I don't want to manage a cluster. I remember that I was able to use public docker registry too but now it doesn't support it...
Why Google Cloud Run doesn't support them anymore and will it be supported eventually?
Google Cloud Run Managed does not support incoming UDP connections.
If you review the Container Runtime Contract, your container must start an HTTP server and respond to HTTP requests.
The only container registry that Cloud Run supports is Google Container Registry.
I was part of the alpha and betas for Cloud Run Managed. Neither UDP nor public container registeries were ever supported.