comments:
Are you familiar with programming? I built control boxes for my Playstation compatible pads using the RP2350-Zero ( https://www.amazon.com/dp/B0DYTVCF2H ). The first time I did it with CircuitPython, then re-did it with Arduino for more precise timing control. The CF pad should be even easier, since you're just reading inputs instead of dealing with the Playstation controller protocol. It shows up as a USB gamepad. The board is really small, so I 3D printed a small shell that fit the board and a DE-9 connector. https://imgur.com/a/lfT6aPa . A HD-15 connector should fit the same. While what I did wouldn't be a "drop-in" solution for you, I'd be glad to share the files, which should get you there with little effort - other than physically building it, soldering wires, etc.