"Emulation" is a catch-all term that includes binary translation, static and dynamic, which every modern emulator uses (Apple just doesn't want you to use that name because people think emulation is slow). Rosetta2 is not a pure static translator, because such a thing can't exist (see: self-modifying code).

Just because binary translation is used doesn't mean it's magically as fast as native code. Converting code that runs on architecture A to run on architecture B always has corner cases where things end up a lot slower by necessity.