Are Raspberry Pi devices free of hardware spyware (Intel ME/AMD PSP)?
Are they truly secure devices if booted with the correct OS?
Remember that the RPi SoC isn't primarily ARM. There's a multistage process to boot the VPU/GPU which in turn runs the ARM as a sort of child.
Afaik only ARM chips have no ME and PSP. Since ARM is British they should also be infected though. Your best bet is to wait for a EU chip.
Thats a really good question. My money is on NO.