The P4 is pretty high spec with a 400MHz dual-core RISC-V

At 8 MHz, a 68k can execute at most 2M instructions per second. So the answer is going to be yes, if this manages to execute one 68k instruction per ~200 cycles.

I think executing an instruction is going to be closer to 20-50 cycles than 200, so it should be much faster than a real 68k CPU.

I think performance is likely to be in the ballpark of a 68040 @20 MHz, but that's just a guess. This would leave 20 cycles for each emulated instruction. With JIT you could reach 200 MHz+ comparable speeds.

Yeah, the first thing I thought of when seeing this was "how long till this tablet thingy will be out of stock everywhere?".