Just purchased a Radcity 5 Plus for the wife at the end of June/23.  Only put 16 miles on it before the controller stopped sending power to the rear hub with PAS or throttle.  Able to get a replacement controller after trouble-shooting and sending iphone movies with Rad Chat.  Under a week to arrive and a real PITA to replace.  The new controller cables were too long and couldn't secure the two screws for the controller from the outside of the frame (couldn't line up the holes in the tight internal space near the pedals).  The new controller worked and back on the road again.

The wife's brand new 2 week old Radcity 5 Plus with 16 miles had the no PAS/throttle issue. Worked perfectly before that until it didn't.  Double-check all connections, brake lights, brakes, etc...  All displays worked as normal with no error codes including showing mph on speedo when spinning the rear tire by hand.  Trouble-shot with Rad chat and they eventually sent me a new controller.  A real PITA to change out the controller; but, resolved my issue.

Having the exact same issue with the Radcity Plus Step-thru I purchased in July with 17 miles on it.  It ran perfectly until then and just stopped the next morning.  Displays work and you can up/down the PAS levels.  Zero power to hub motor with PAS or with throttle.  No brake light on and no change if I pump the front/rear brakes with brake light working as normal to see if the motor cut-off is engaged.