There's a real classic called Binary that's even harder. There's even a metagame, "Bughunt", where you get a fly swatter and travel down endless corridors of tubes searching for bugs before they land. Urban legend is there's a game that is the most perfect grind ever, called Unary. It's basically the Platonic Ideal of Grind.
Valheim!? The whole reason one picks Rust is to avoid the 'grind