Yes, we use just the first reference you send me. The problem is --os flag don´t include debian-10. It includes only debian-8 and debian-9.
We think many people using Bitnami Redmine stack, have the same problem, because this stack uses Debian 10.
Sure, we can install a Debian 10 images and replicate all configuration from scracht... but this is very painful.
Then, it is what I want to know... how to migrate from an OVA image to a Debian virtual machine in Google Cloud?