It also depends on the architectures. x86 on ARM is tough to do efficiently because of the memory model differences. One of the keys to Rosetta 2 being so good

It also depends on the architectures. x86 on ARM is tough to do efficiently because of the memory model differences. One of the keys to Rosetta 2 being so good was being able to make the underlying ARM processor obey the x86 memory model (even though it was still executing ARM instructions).