After shutting down several popular emulators, Nintendo admits emulation is legal
(www.androidauthority.com)
Why should that change the legality of the situation? Not to mention the Nintendo Switch is already quite old and emulator development (for the most part) hasn't lagged much behind a consoles release. Getting paid for emulator development also isn't illegal and I don't see why it should be. You're trying to conflate emulation and homebrew development with piracy which doesn't seem fair (and doesn't even require emulation, which you've illustrated with your Nintendo DS example).