It feels like it's just not possible in general to emulate the full instruction set of any CPU with an MMU with an acceptable performance to run modern software. QEMU running Windows for x86 on an M1 isn't very fast either.
Only emulating the portion of the instruction set available from the userspace is another story though. At least the way Apple does it with Rosetta and Microsoft with whatever their thing is called, you don't even notice that an app is running under emulation. The only giveaway is that it takes a noticeable time to start for the first time while the code is being translated. It's truly impressive.