It appears your problem is regarding setting Environment Variables correctly. After installation, the command psql won't work because you need to set the correct PATH to this command in your Environment variables file - which will differ a little according to your version.
I just wanted to add a comment here for future inquiries.
I'm working on a MacOS ...
It's typically not necessary to use custom templates and installation for SQL Server on Azure Virtual Machines. The Azure Marketplace has an extensive collection of pre-configured templates for SQL Server on Azure Virtual Machines, which you can deploy through the Azure Portal or through Powershell. These are built and maintained by the SQL Server ...
Here you will find a template that shows how to create a SQL Server VM in Azure configure with 2 managed disks. One disk is for SQL Server data files and the other is for SQL Server backups. For more information, please click here.
This is only a matter of the metadata being incomplete in the installer.
If you have access to Oracle support, then:
Reference data is not available for release "12.1" on Linux x86-64 SLES-12 (Doc ID 2127760.1)
In the above note, there is a link for the patch for this issue.
The workaround is to ignore the prerequisites by starting the installer as: