At which point it seems like AMD would be the better choice based on the price/performance and their support for features like ECC memory that Intel disables on its consumer-grade CPUs. Unless Purism wants to look into a POWER-based system.
I did a search to see if there had been progress on disabling the PSP, but unfortunately found nothing promising. A group called CTS Labs claimed to have found 13 vulnerabilities in AMD CPUs in 2018 which they called AMDFLAWS, and even said they were interested in working with libreboot/coreboot to get them to run on AMD CPUs, but aside from one talk in 2019 (after all of the vulnerabilities were patched) and apparently an initial disclosure report that is no longer available, they haven’t published anything and there doesn’t seem to be any current effort on their part to contribute to libreboot/coreboot. Linus Torvalds said it was all an attempt to manipulate AMD’s stock, and given that CTS Labs seems to have gone completely dark after this talk (their AMDFLAWS technical paper is still “coming soon” on their website) I’m inclined to agree. Even if that’s not the case, they apparently have no real interest in making these exploits useful to free software projects.