The Home Assistant frontend can definitely add support for embedding ingress panels (addon pages) in dashboard. But I see this issue is reported as a configuration and not as a feature request, so I’m not sure if it was ever taken as a feature request by the frontend team.
An iframe is a way to do it.
Example from my config:
type: iframe
url: >-
https://grafana.mydomain.com/d-solo/1PWOjOcnz/technical-data?orgId=1&theme=dark&panelId=5
aspect_ratio: 35%
So do you just expose your Grafana entity to the internet?