Hi Jonathan,
Please carefully follow my instructions below to create a new Service and subscription limits (quotas) request quota increase to allow access to deploy Zone Redundant PostgreSQL Flexible Server in the region. Note that they may not approve your request due to capacity constraints.
1. Navigate to this link to start the process:
https://portal.azure.com/#create/Microsoft.Support
2. Enter quota in the box and click Go
3. Select Others / Service and subscription limits (quotas) and click Next
4. Click Create a support request button, as shown
5. Select Issue type: Service and subscription limits (quotas), Subscription, Quota type: Azure Database for PostgreSQL Flexible Server, click Next
6. Now you should be on Additional details tab. Click Enter details
7. For quota type select Region access with zonal dependency (Availability Zones), select Location, enter expected number of vCores, and then click Save and continue
8. Finish filling out Additional details tab, click Next, review and click Create. You should receive an automated email within a few minutes.
Please click Accept Answer and upvote if the above was helpful.
Thanks.
-TP