Nintendo succeeded in killing Yuzu because they had decryption keys which Nintendo could argue is breaking their copy protection, which is why they settled for 2.4 million dollars in sales damages because they knew they wouldn't be able to win in court.
All of these forks have since removed the key and require the user to supply it (legally from your own console).
So in theory they should be protected under US law since emulation and reverse engineering is completely legal.
However
Nintendo also has infinite money to throw at the problem, and FOSS devs are usually not willing to deal with insane amount of personal liability because of a hobby, which is how they killed Ryujinx.
So you better hold onto your guts if you plan to fight Nintendo.
Or move to i2p so they can't disable you lol.