An Audiofront MIDI expression would do it. They take a variety of footswitches (latching or momentary) or expression pedals and turn them into MIDI controllers with programmable cc’s. The inputs are TRS so the single input version can take a two button footswitch. If you need 3 buttons you gotta buy one with more inputs. Ive used one one a Helix rack so it’ll work for you.
https://www.audiofront.net/MIDIExpression.php