Another Total Anhilation clone is ZeroK which is unfortunately also not completely open source because of its artwork license (Wikipedia mentions CC by NC ND but I could only fjnd this summary https://github.com/ZeroK-RTS/Zero-K-Artwork/issues/16).
Unfortunately it is near impossible to setup a local LAN game with ZeroK, since there are no current instructions to setup the required spring-engine lobby server.
Edited, because I recognized to late, that Wikipedia mentions that zeroK-Artwork might also be under CC-by-NC-ND.
Edited again to clarify, that its not open source because of the artwork.
Maybe drop by the Discord to see if anyone can help you debug the issues you've run into.
Also, just because it might be hard to use on non-closed systems doesn't make something not open source.
It's somewhat easier for BAR despite in theory being harder due to the lack of these standalone files due to the rapid file system, but in practice easier because you can just use the unofficial Skylobby (BAR still uses Springlobby protocol, at least for now).
If so, that is a serious impediment, tbf.
Unfortunately non-open source artwork is a problem with many games whose sources were released by the original publishers, after they abandoned any commercial plans.
For example I'm a big fan of OpenRA, but its artwork is still non-free.
I think ZeroK is a great game, and BAR probably also, so I didn't mean to distract from the great accomplishments of its FLOSS gameengine authors.
Some aspects vaguely look like C&C Generals, and some like Starcraft, if I'm understanding stuff from the video correctly. Thanks for sharing!
Yes, it's fully playable (and indeed being played by thousands of people) right now.