Emulator developer here (not for videogame consoles but IoT and Honeypots). The DRM circumvention that Yuzu implements can be attacked legally twofold. The decryption process to run a game in the Nintendo Switch uses some alphanumerical keys stored in 2 files if I remember correctly, called "prod.keys" and "title.keys".

Yuzu did not distribute those.

However it did implement the code to use those keys and decrypt a game. So you could say the final compiled binary "implements a way to circumvent DRM". Although you could also defend it by saying "it just models what the hardware does".

Regardless, for the whole "emulators are illegal" discussion, you could technically distribute code for an emulator that does not include that piece of code. Then "ask" your users to "search" for it (kinda like with prod and title keys) and "tell" them to compile it.

But these are very technical arguments you would need to pass in front of a non-technical judge. So good luck.