IANAL, but from what I read regarding Yuzu / the title and prod keys / etc., is Nintendo's argument is three-fold -- the only way to obtain those keys is to use a tool that itself is a violation of the DMCA, use of those keys by an emulator to decrypt Nintendo's protected content in a method outside of Nintendo's authorized use is a violation of DMCA even if the keys aren't provided in the emulator, and there is no legitimate use of those keys except to circumvent controls intended to protect copyright.

Therefore, by their argument, any emulator that can use those keys would effectively be subject to DMCA even if you had to bring your own keys, because unless the emulator only ran homebrew or completely decrypted content and had absolutely no decryption capabilities, you'd still be using the prod keys and title keys to decrypt content in violation of the DMCA in order to execute it. So, the tool that dumps the keys is a DMCA violation and any emulator that uses those keys to decrypt protected content in order to execute it is a DMCA violation, and Nintendo has a strong case that the actual keys themselves are only useful for making unauthorized copies of content that bypass the encryption that exists to prevent it.

It stands to reason that a clean-room developed Switch emulator that required all content it ran to be decrypted prior to being able to run it may be able to exist without Nintendo shitting it into non-existance, since Nintendo couldn't make any argument that the primary use was a DMCA violation as no encryption would be being bypassed by the emulator. They'd probably then go after whoever made the tool to dump the games, but they'd probably be less successful.

On the other hand, the pragmatist in me says that unless I was 500% sure of my online anonymity, I wouldn't want to pick a fight with Nintendo -- even if I thought I was right. They have enough money to lock someone up in legal battles for a very long time and most independent developers wouldn't have anywhere near the finances required to bankroll appropriate defense counsel. Can't say I'd blame people for not wanting to invite that hellscape into their lives.