I tried getting a Netgear A6200 based on advice from reddit that it would work, but windows 10 doesnt seem to show it supporting miracast.
If i remember correctly, you need more than just a compatible wifi adapter... your video chipset AND cpu have to support it as well.
One thought, is it very difficult to install a laptop wifi card into a desktop PC? I've never looked at it (never bothered replacing a laptop wifi card), but assuming they're PCI-E rather than some specific laptop or proprietary connection it should be do-able? That would solve the problem.