Hasu USB to USB Controller Converter
https://1upkeyboards.com/shop/controllers/usb-to-usb-converter/
Turn almost any USB keyboard into a programmable keyboard!
This converter, created by Hasu, allows you to change the keymap and add functions through TMK firmware.
The Hasu convert is a man in the middle between your keyboard and your computer, allowing you to re-program button behavior before your PC even sees it. This allows you to customize any keyboard's behavior with TMK/QMK custom macros, or just make it easier to remap really stubborn keys like the modifier and toggle keys.
See Linus Media Group's Taran's video on it here: https://youtu.be/GZEoss4XIgc