Installed the Nyon controller on my Synapse NEO 2020 and it is fantastic. Maps load effortlessly, easy sync with the Cannondale app, and uses very little power. Slick!
I know they stopped supporting the Kiox. I usually use the nyon for navigation if I need it but you need to make sure you setup the route before hand. but I don't do that much navigation so not sure how robust it is in hard use.
I got my Garmin before Nyons were available, so I use both, mostly for radar temp evaluation, slope, and such. I also used it to recorded to strrava till bosch made that work well.