The kernel is GPL, so it is hard to get support for hardware with drivers without GPL, it does not conform Linux' license.
It's a violation that's not enforced, as almost all distros provide proprietary blobs. They balance ideology with usability, since they realised most people aren't going to use a librebooted ThinkPad from the 90s. If everyone enforced libre purism like GNU, desktop Linux would've been completely dead long ago. If you need proof, check usage statistics for any of the free distros.
I, too, had also nothing but hassle with an NVidia graphics card in Debian.
And did you need to install a modified iso to have WiFi? Did maybe Debian provide those nvidia drivers?
The other thing... let's turn the question around. Would you:
How is any of that relevant? This is not a question of additional software or services, but basic usability. Guixos as is, is for example essentially useless on a laptop unless you're willing to carry an external WiFi card in your pocket.
If not - why do some people expect equivalent things from free software projects?
The only expectation I have for an OS is to work on my devices, guixos does not. And even when I jumped through all of the hoops to get it working, I still needed to use nix to install most packages I need to work. So why would I use guixos+nix+flatpak instead of just running nixos?
I honestly never tried them as they don't fit my use case, so I can't comment. The concept does sound good though.