Hello, you have several options. For switches, buttons and rotaries I would not use Dcsbios as that will limit its use to a single aircraft.
It is best to use usb controller boards so they are recognized as a keypad or joystick There are several options ...
Leo Bodnar, the simplest but most expensive.
Arduino with joystick library, very cheap but needs some programming.
My favorite Arduino + mmjoy2 + cheap shift register from aliexpress.
DcsBios is ideal for exporting led warnings lights, or radio frequencies to 7 segment panels.