I heard about this through a story about the scummy copying from some extremely gross individual for 'their' game that's getting a paid Steam release. and I just want to say THIS should be on Steam. I'd buy this. not just to support you, it and the idea of creative integrity, but because it's fun as a bunch of tennis balls. good stuff. keep this up!
General Steam exposure, legitimization as a dev/pub by padding release list, monetization via item drops, monetization via telemetry (if injected), monetization via cryptominer (if injected). There are many ways to gain from Steam by publishing a free game.
Please, get an attorney and have them file a DMCA (which proxies out your personal information from being communicated to the thief). People like this don't deserve to get away with their crimes.