Welcome to the site and thanks for digging further into these.
Well, if OpenRA is too much, what about updating the port of FreeCnC? It came out sometime around 2008 but lacked sound and I think was an early beta release.
https://sourceforge.net/projects/freecnc/
The homebrew game can be found in this compilation CD created by IberDC.
http://dcevolution.sourceforge.net/inde ... berdc_2010