Just last week, on Tuesday, February 26th, 2024, news broke out about the Yuzu emulator team being sued by none other than Nintendo themselves, with Nintendo claiming that the emulator apparently allowed users to play certain games early (due to street dates being broken) and also allowing...
It’s really just that they profited from it.
If it was more than just that, they would have, or will in the near future, go after Ryujinx or the many incoming forks of Yuzu.