I"m no help. I ride fix gears for their pure simplicity. You pedal. You go. (I do change gear ratios often on a couple of my fix gears. I figure I've earned that right, having ridden them for 40 years into my 60s.) So they have almost no electronics. A taillight. Sometimes a headlight. Occasionally a heart rate monitor that I usually forget to look at. Dumb cell phone in my pocket. A moderately capable brain between my ears I sometimes turn on.
Ben