I got the Teensy 2.0 board described in the project, did not bother with an Arduino but it seems to be plausible to get it running with that as well.
Make sure to do at least a half-decent job at soldering pins on the Teensy board, otherwise it gets hard to find if there's any issues with the circuit or the hardware itself when the thing inevitably doesn't work on the first try
The optional capacitors in my case turned out to be mandatory, the force feedback effect did not function correctly otherwise
Once the circuit is built correctly and the Teensy code has been uploaded on to the board, unplug the usb cable from the motherboard. Make sure the joystick is plugged into the circuit and also make sure the force feedback power adapted is plugged into the joystick and and powered on, wait a bit then re-plug the usb cable back into the motherboard
If all has gone well you should hear the generic usb plugged in sound and after a bit of waiting the device shows up under "Setup USB game Controllers" as "LUFA Joystick wFFB" then you can click properties and test the axes and the buttons. For whatever reason the big arrow button under the throttle did not work on my stick, maybe my particular button is broken, not a big deal.
The stick light indicator should be green, if it is constantly blinking then the force feedback adapter is not plugged in properly.
After being plugged in for the first time the stick should NOT be resisting your movements on the desktop, it should only do that when inside a game.
And all that's left to do is find an old game that support FFB and enjoy ^_^ I went with the good old Microsoft Combat Flight Simulator games, the first game has a lot of issues but the 2nd game works out of the box and recognized the joystick without any hassle. The games are abandonware and pretty easy to find online.
Here's some list of of old games that support FFB:
The most modern game series that still supports FFB seems to be the IL-2 series. It's really a shame that Microsoft abandoned this tech and tried to bury it. It's got a lot in common with the recent PS5 controller haptic feedback, but it was being done back in 1998. Kinda mind blowing how Microsoft crippled and damaged the PC gaming space between 2001-2014
Apparently this person managed to get his alleged "FFB Gamepad" to mimic the generic gamepad rumble and have it be at least functional in games that only support XInput: https://github.com/ValveSoftware/Proton/issues/2020 But he claims this only works on Linux and I don't really have time to test that at the moment.