This button box can implement a matrix approach in order to implement several buttons in a small amount of pins, also implements diodes to provide a fix for the ghosting and masking problems present in this type of approaches.
However, due to some technical limitations when doing the key binding in the current state of MSFS2020 is not possible to map all the buttons available in game, so using Mobiflight with Custom Events, can give us access to new key bindings, with the down side that a key matrix can't be implemented here, and each input need to have an unique Pin configuration in the Microcontroller causing a lower number of inputs.