The main freeciv21 developers you can see on the repo are mir3x and lmoureaux. The original freeciv project still has some activity, but we wanted to iterate faster, focus more on multiplayer, and allow modern C++ language constructs to make development easier.
Are you a full time developer? Our startup is currently working to bring Unreal Engine to the web, we've also done various ports of classic games to WebAssembly. We're building a platform and suite of optimization tools to enable any game developer to be able to deploy 3D games and apps to the browser. WebAssembly, WebGPU, and WebXR are going to disrupt the games industry and create a whole new platform category that doesn't revolve around 30% fees or walled gardens. It's also the path to the metaverse.