In Server 2012 R2 it was possible to manually install the RDS Gateway role without needing an entire RDS deployment.
In 2016, the Gateway component is missing - as can be verified by running Get-WindowsFeature in a Powershell prompt. It seems the only way to add the component is to do so after completing a RDS deployment.
Is there another approach that will allow use of RDS Gateway as a standalone component?