I admire your level of purity, but your distinction is not helpful in laptop selection.
I'm not aware of any FOSS operating system that only uses totally open source hardware drivers. even GNU HERD would run proprietary drivers if they actually ever finished.
For Qubes, I'm not sure how you can have a better approach to isolating binary drivers, then running them in a totally contained virtual machine.
Which operating system are you referring to without drivers?
I'm not super informed about the kernel layer, so forgive me if this is a silly question, but how does that approach compare to atomic distros like Fedora Kinoite, UniversalBlue, or NixOS?
It's all about where you draw the abstraction layer in the hardware stack.
For Qubes / Xen its done at the Virtual Machine layer (pretending to be totally independent CPUs/RAM/Networks)
For Nix et al I believe they are using containers which draws the line of abstraction inside the Kernel (pretending to be different clean name spaces, but the same kernel is aware of what is running everywhere).
There are tradeoffs and different efficiencies for every different level of abstraction, for the most security sensitive applications you would want to run them on physically different computers, then the next step would be inside of different virtual machines (Xen/Qubes), then next step would be in different kernel name spaces (Containers/Nix), then process isolation with different virtual memory spaces (standard linux type processes you know and love)
I'm rather annoyed your acting as a purity commissar in a hardware recommendation thread and you didn't bother to familiarize yourself with the thing your nay-saying. If your going to drop a its not FOSS purity bomb - you should know why!
I'm not a purity commissar and I actually don't agree with the "proprietary software should be impossible to install" thing of FSF. I meant that what runs on the stock Linux kernel may not run on libre kernel and it can't be a benchmark of FOSS support. Also I'm not talking about VMs
Qubes is a framework around XEN, the microkernel to share and isolate hardware resouces amongst VMs. Inside of those VMs you can run whatever operating system/kernel you like.
Qubes is about as FOSS as you can practically get.