Using HTTP2 with GKE and Google Managed Certificates

I am using an Ingress using Google-managed SSL certs mostly similar to what is described here:

https://cloud.google.com/kubernetes-engine/docs/how-to/managed-certs#setting_up_a_google-managed_certificate

However my backend service is a grpc service that is using HTTP2. According to the same documentation if I am using HTTP2 my backend needs to be "configured with SSL".

This sounds like I need a separate set of certificates for my backend service to configure it with SSL.

Is there a way to use the same Google managed certs here as well?

What are my other options here? I am using, Google managed certs for the Ingress not to manage any certs on my own, if I then use self signed certificates for my service, that kind of defeats the purpose.

Google Managed Certificates can only be used for the frontend portion of the load balancer (aka client to LB). If you need encryption from the LB to the backends you will have use self-signed certificates or some other way to store said certificates on GKE as secrets and configuring the Ingress to connect to the backend using these secrets.

Like this https://cloud.google.com/kubernetes-engine/docs/concepts/ingress-xlb#setting_up_https_tls_between_client_and_load_balancer