Blackmagic is a hardware company that also has some software they sell on the side, which is why they've steadfastly ignored fixing their software in any way that would eliminate the need to purchase their over-priced video output cards.
My laptop can output 8K HDR @ 60 fps, which no Decklink card can achieve, at any price. I can get a "clean feed" by simply ticking the "Override to reference mode" checkbox in the NVIDIA driver. Several people have confirmed that this produces bit-accurate output indistinguishable from what a Decklink card outputs.
> fullscreen view on a second monitor
Yes, but it's still not color managed or even enabled for HDR under anything but MacOS! It just outputs the values as-is and lets the OS deal with it, which will treat it as Rec 709 SDR.