https://canoeboot.org/ is developed by the same person who makes Libreboot, and is more updated than GNU Boot.
Although using something like this or GNU Boot will prevent you from obtaining microcode updates, which can leave you vulnerable to exploits. The CPU already has baked in microcode and updates are signed by the CPU designers (AMD and Intel in the case of x86 computers). Regardless of whether you update it or not, it is still proprietary code running on your computer. If you really don’t want any proprietary code running on your computer, just get a RISC-V board (although I’m not aware of any actual RISC-V silicon that is 100% free, but there are 100% free designs out there).
Stallman and GNU never placed much importance on free hardware designs, as normal people do not have the means or the machinary to manufacture something as complex as silicon or PCBs with small details, for instance, but that ignores FPGAs, PCB manufacturing plants, and small-quantity silicon production, which are all more modern progressions of technology.
The purpose of GNU and the FSF is not to prevent supply-chain attacks and to ensure security, but to empower users with the freedom to modify the software that runs on their computer. It just so happens that those idiologies align most of the time.
It is also a bit unrealistic to expect a society to just stop using smartphones, so we should be working on creating fully free smartphones, which are projects that some companies (Pine64, Liberux, Purism) are working on accomplishing. Even those phones still use ARM SoCs and proprietary modems. The proprietary modem problem especially is the biggest one, as getting something like a software defined radio certified by both cell carriers and the respective government organizations is a beast in itself. Every device needs a valid IMEI code to use a SIM card, after all. Also I believe SIM cards themselves can do processing, but don’t quote me on that.
Not to mention the fact that there are no WiFi chips that work without firmware blobs that operate on any standard newer than 802.11n. SDRs might be more feasible here, but government regulation would still be a problem. https://github.com/Nuand/bladeRF-wiphy/
If you’re looking for a RISC-V laptop, Framework has a board available based on the semi-popular JH7110 SoC used in the VisionFive 2: https://frame.work/products/deep-computing-risc-v-mainboard
I personally have a GNU bias as well (watching Stallman talk is what got me into free softwars to begin with), but the allowing of non-free software is in Libreboot and not canoeboot. Canoeboot was created as a direct response to GNU Boot, since GNU Boot is just a fork of Libreboot with all blobs removed, but it wasn’t being rebased often, if at all.
https://canoeboot.org/news/policy.html
I linked one at the end of my post. Not going to be cheap, though, since it’s Framework. It’s also not going to be very fast. I don’t think the board is free, but niether are any Thinkpads. There is freely licensed official documentation, though for their laptops, although I’m not sure about the third party RISC-V board: https://github.com/FrameworkComputer/Framework-Laptop-13
As for the point about security, in the cases where it comes to state run cracking groups or other high skilled crackers like what is mentioned in the linked article, it is not enough to just have as free of a system as possible, but also as secure and updated of a system as possible. You mentioned in your top level comment that people should use devices that run 100% free software as a direct response to this news article, but leaving any gaps open will allow for these crackers to infiltrate. The plain and simple version is that both are important.
Does the X200 even support VT-d to run something like Qubes with a Linux-libre kernel?
You also didn’t cover the point about embedded firmware blobs, like embedded microcode in every x86 CPU since the Pentium Pro, and not just microcode updates.
Also maybe separate your points into paragraphs for legibility.