the zone does not have enough resources available to fulfill the request/ the resource is not ready

Even I'm getting the same error. I have waited for 24 hours and tried. But still no luck. For me, it's not transient.The zone 'projects/XXXX/zones/europe-west2-c' does not have enough resources available to fulfill the request. Try a different zone, or try again later. I had to create entirely new instance to come over it.

So I had the same issue for over 24 hours.

I tried to move my VM to another zone, but since it was in the terminated state and I couldn't restart it due to not having enough resources in my region, I couldn't move it.

Okay, but then per my understanding, your persistent disk attached to your VM is another story and you can copy it without starting your VM.

So I went around this issue by:

1. Going to my Google Cloud Platform >>> Compute Engine
2. Went to Snapshots >>> created a snapshot >>> Select your Compute Engine instance
3. Once snapshot was completed I clicked on my snapshot.
4. Ended up under "snapshot details". There, on the top, just click create instance. Here you are basically creating an instance with a copy of your disk.
5. Select your new zone, don't forget to attach GPUs, all previous setting, create new name.
6. Click create, that's it, your image should now be running in your new zone

First of all our apologies that you’re experiencing this issue and great to hear that this issue is being resolved for you.

Our goal is to make sure that there are available resources in all zones. This type of issue is rare. When a situation like this occurs, or is about to occur, our team is notified immediately and the issue is investigated.

We recommend deploying and balancing your workload across multiple zones or regions to reduce the likelihood of an outage. Please review our documentation which outlines how to build resilient and scalable architectures on Google Cloud Platform. As you have noticed that trying again in the next few hours fixed your issue, as this is a transient error. It should not last long. Since our system is dynamic and always expanding, in this type of situation I would recommend you to create your instance in a different zone or try later which you have already seen in the error message.

Additionally, I'll also recommend reviewing this link that recommends distributing your instances across zones to increase availability. You can also review this other link, where you will find some best practices for designing robust systems on GCE (Google Compute Engine).