I believe, that few, if any of the currently supported boards feature all of: USB Device Port, HDMI-Port (or sufficiently fast USB-Host-Port for Capture Adapter), HW-Video-Encode (or beafy enough CPU), enough available (programmable) GPIOs

I think with Wifi 6e and 7 this is no longer true. Most of these devices are really powerful supporting at least one usb3 port. This is probably no longer a problem in the near future, especially when 1080p is enough.