They give you pretty much all control of the hardware. The ultimate sign of that is, that you can install Linux on the ARM macs now. Apple even made some steps

They give you pretty much all control of the hardware. The ultimate sign of that is, that you can install Linux on the ARM macs now. Apple even made some steps to make this reasonable. You do have full control of the hardware. On the other side, a booted macOS has certain limitations in place. Not even root is able to write to certain partitions and such stuff. This is not because "we know better", but because these limits provide some fundamental security. A partition which cannot be written to, cannot be modified by malware. You can boot into a mode where this protection does not exist, but for productive usage, it is a good idea to have that protection in place.