Choosing Hardware: cpu, motherboard

[znavko]

Hello, hackers!

I am choosing my new desktop computer configuration using catalogue of free hardware  https://h-node.org/hardware/catalogue/en . There  are not cpus and motherboards.

I am not sure Ryzen 7 is what I need, cause I do not know how to choose top cpu without vulnerabilities.

I've noted that Minifree X200 goes with Intel SL 9400 https://minifree.org/product/libreboot-x200-tablet/   , but excuse me 1.8GHz is too slow even for booting GuixSD.

Also, I've found TaurinusX200 https://shop.libiquity.com/product/taurinus-x200 but there is not specified cpu, only Intel Core 2 Duo 2.26-2.66 GHz (?).
I've found Talos II Lite here  https://secure.raptorcs.com/content/TL1BC1/purchase.html but I think GuixSD has no IBM Power9 support.

I'll try to flash motherboard with Libreboot or Coreboot, so I need compatible motherboard. Here are some cpu boards https://www.xes-inc.com/product-category/processor-boards/  but I think that is not my variant.

Would you be so kind to advise secure cpu with 3GHz or higher frequency and coreboot/libreboot compatible motherboard  for desktop pc?

Hope, you have a time for this!