I have a Librem 15v3 and coreboot. I had the same issue with Qubes 4 RC2 and not supported hardware. Checking cpuinfo on that OS does show a lack of vmx, etc.
I wanted to use the laptop while waiting for this fix, and installed Linux Mint. When looking at cpuinfo there, I see ept, vmx, and all the necessary features. It appears that coreboot exposes this correctly for Linux Mint et all, however, the mechanism that Qubes uses to detect hardware support has this masked, even at the lowest level. Thus, there is likely some other solution required, and not a coreboot update