Evict node from SQL Server 2016 Cluster on Windows Core
Use the command-line parameters for setup.exe on Windows Core.  The details can be found at Microsoft Docs.  Using the command-line parameters allows use of the setup.exe without requiring the GUI pieces, which are problematic on Windows Core.

From that page:


  Use the parameters in the following table to develop command-line scripts for RemoveNode. To uninstall a failover cluster, you must run RemoveNode on each failover cluster node. For more information, see Always On Failover Cluster Instances (SQL Server).


A simple example, taken from the page linked, is:

setup.exe /q /ACTION=RemoveNode /INSTANCENAME="&lt;Insert Instance Name&gt;" [/INDICATEPROGRESS] /CONFIRMIPDEPENDENCYCHANGE=0