It sounds like it does limit current as you say at 20kph the current is near half, you may not be able to adjust it via the display but it does via internal programming.Mine draws around 10a at 30kph. If I back my speed down to 20kph the current draw is near half, therfore doubling my range.
That controller is supposed to current limit, however I've never been able to get it to work.
I really like the look of your bike, long wheel base, proper front mudguard ending in line with the bottom bracket, sensible saddle and handlebars.Mines rated at 36v 250w however a draw of 10a at 36v means in reality its around 360w.View attachment 34646