Hi @charles
If you are not able to create server in any of the region, you may need to request capacity for your subscription.
To do so, you will need to create a ticket with Azure at Billing/Subscription management at https://azure.microsoft.com/en-ca/support/create-ticket/
Also, check the regions where MySQL Flexible server creation supported.
Azure Database for MySQL - Flexible Server
https://learn.microsoft.com/en-us/azure/mysql/flexible-server/overview#azure-regions
Thank You!