In order to asses a game's success, you have to take into account the budget. Undertale sold 1-2 million copies and Cyberpunk 2077 sold ~15-20 million copies; but it'd be an extreme stretch to say that CP2077 is more successful than Undertale.
CP77 is a successful scam. Note that you have to take into account the value of the company. Despite CP77 generated money for the game itself, CDPR stocks dropped more than 50% therefore the company lost more than gained by CP77 sales.
