Bubbles making it open source would be very beneficial even if plutonium took down the source code someone would have it downloaded and be able to share it especially if you made I don't know say a torrent that anyone could seed? I understand the devs don't want people to steal their code but it seems like its only a matter of time before the project gets taken down. Also whether the c&d letters stop is completely irrelevant someone will eventually host it in a country with more relaxed copyright laws this has happened for other games before eg Phasmophobia

you don't need the game on steam to use plutonium