Mobile experience isn’t that great on little screen
Here a little concept that I did with paint : https://imgur.com/a/QbHZPHq
As you can see it doesn’t need a big overall of the current UI, it’s just a little improvement.
To each quarter of the screen correspond an input/output (see picture)
By default the zoom is locked on a pedal, and you jump to another pedal by swipping in a quarter.
To add a pedal, you long press on a quarter you want to connect a pedal to, then a list popped out letting choosing you a pedal.
Of course it can be improved.