There’s also a ‘is note on’ and ‘is note off’ method. You can 100% visualize midi data with the midistream, I don’t know what alternative solution you already made but the harmonix framework is pretty robust and it supports this exact usecase.
Here’s a small example I made using the harmonix midistream output driving a blueprint keyboard visualizer - https://www.youtube.com/watch?v=jldTWFm_YBk&list=PLnC4434gGyWHi6OtNmQmJqOdjTMzaERWO&index=7