Zero-K is a similar game (also opensource, built on same engine, slightly different design goals):
https://zero-k.info/ https://store.steampowered.com/app/334920/ZeroK/Zero-K simplified the economy (metal cost = energy cost) but added a whole lot of mechanics like overdrive grids and made every unit unique. There is a lot more unit variety with mind-control, jumpjets, shields, unit-throwers, self-replicators, teleports, terraforming, etc.
Their design blog is also very interesting: https://zero-k.info/mediawiki/Cold_Takes