Migrate from GKE Istio add-on to open source Istio

Hello

We are using GKE Istio add-on version 1.6.14-gke.1.

We are considering migrating to the open source version of Istio. Google documentation mention that this is possible to do but not how you do it. So if we want to do the migration would it be possible to follow the canary upgrade to istio version 1.7.8?

Does anyone have experience with Anthos Service Mesh? Im just wondering if you install Anthos service mesh in one cluster do you then have one Anthos Service Mesh client? Or is an Anthos Service Mesh client something else?

Thanks