Having a crack at this, but finding that after around 1 hour of 'Still creating...' in our Terraform Apply stage in our Azure DevOps pipeline we get a '##[error]The operation was canceled' message and the Terraform Apply stage aborts. The Managed Instance create operation is still reported as in progress in the Azure Portal, but we'd need to do a manual Import of the deployed resource in to the Terraform State file since Terraform thinks it didn't finish deployment.
Tried adding a Timeouts block to our azurerm_mssql_managed_instance resource, but the default timeouts are already supposedly 24 hours for creation, Terraform doesn't seem to pay any attention to them.
Any ideas on how to get a successful deployment of the azurerm_mssql_managed_instance resource UrosMilanovic?