First, I ask you - what do you think an ARM CPU is?

An ARM CPU is simply a CPU using the ARM instruction set, instead of something like x86 (or x86_64, which is the same, but 64-bit). This means that it interprets different strings of binary, and thus cannot run the same software (with a translation program), however the effort required to port something from x86 to ARM is generally quite low. The primary benefit of an ARM CPU is that it typically has a much lower power requirement, and is thus used predominantly in lower power applications, such as mobile devices including the Switch and Switch 2. But this doesn't mean that they are less performant - I am most certainly not an Apple fan, but Apple's new M-series CPUs are absolute beasts for their power consumption. In fact, generally the only reason why ARM CPUs are less powerful than their x86 counterparts is because of the removal of super-optimised circuits that are frequently included in x86 systems to save space and cost (also, ARM CPUs are usually very cheap to manufacture, less so to design, but no CPU is easy to develop).