Issues with Stronghold Legends showing "input not supported" a Blank Screen is shown or Crashes.

1. Run the game in a Window

2. Ensure the Hz is correct

3. Ensure the Resolution is correct for your display

Ensure 'Show graphics settings on startup'

In the graphics panel. Click on the General tab and select the Screen Resolution and Hz.

Try the game on this setting and perhaps a couple of others.

If this does not work click Windowed Mode and try the game..

Otherwise, edit the the graphics settings text file.
Located here -

C:\Users\<USER>\Documents\Stronghold Legends
StrongholdLegends.GraphicsSettings.xml

<resolution width="1920" height="1080" format="R5G6B5" refreshRate="60"/>
change to an appropriate resolution

<windowed enabled="false"/>
change to
<windowed enabled="true"/>