Thank you for your reply 
So you don’t even recommend using Qubes certified Laptops (coreboot + disabled ME) ?
In case it is still the best option available at the moment, which one would you recommend between StarBook 14-inch – Star Labs® and https://shop.nitrokey.com/shop?&search=nitropad That they have Tamper Detection Through Measured Boot through NitroKey usb key ?
Could you point me to some Risc-V and OpenPower solutions already available to the public?
One last OT question: what you think about Google Pixel phones with Graphene OS ?
Thank you again
P.S.: About the old Think Pad, at this link (Introduction to Apple Silicon · AsahiLinux/docs Wiki · GitHub) they say:
" This puts them (Apple silicon) somewhere between x86 PCs and a libre-first system like the Talos II in terms of freedom to replace firmware and boot components; while a number of blobs are required in order to boot the system, none of those have the ability to take over the OS or compromise it post-boot (unlike, say, Intel ME and AMD PSP on recent systems, or the DMA-capable chips on the LPC bus running opaque blobs that exist on even [old ThinkPads](Technoethical X200 laptop | RYF))."