Here's something to bake your noodle:
Apple makes Lightning to HDMI dongles that contain 400 MHz Samsung ARM SoCs and 256 MiB of RAM onboard.
They run frickin' Darwin.
There is more power in one of those dongles than there was in the OG iMac, and it runs a cut-down macOS. No cap.
And yes, Doom has been ported: https://m.youtube.com/watch?v=4XCkeN0XuqA
"it is tempting, if the only tool you have is a hammer, to treat everything as if it were a nail." -- Abraham Maslow