I think it's difficult on Intel to be fully free because of Intel ME. As far as I know, it's not possible to fully be rid of it, so you'll always have some prop

I think it's difficult on Intel to be fully free because of Intel ME. As far as I know, it's not possible to fully be rid of it, so you'll always have some proprietary blob running a possible backdoor. If you want to be fully free, you may be interested in the Raptor Talos II, which is based on OpenPOWER and has free firmware. It is pretty pricey however.