Do you have a handy link for the idea that the Pico 2 runs an ARM emulator? That's not an idea I've seen. (Of course, it could, and it can, but I've not seen anything official on those lines.) Edit: see below...
My understanding is that it has two ARM cores and two RISC cores, and two active slots each of which can be set, at reset time, to either flavour. The user's boot-time software is compiled for one or other flavour, and if the boot-time core detects that the image is for the other flavour it causes a boot into the other flavour. (
Ref and also
Ref)
Edit: ah, I see
here this
Quote:
Most bootrom functions are written just once, in Arm code, to save space. As a result these functions are emulated when running under the RISC-V architecture. This is largely transparent to the user, however...
and
laterQuote:
This part of the ROM contains the NSBOOT (including USB boot) implementation, as well as a RISC-V Armv6-M emulator which can be used to emulate most of the bootrom on RISC-V processors.