The bike shows br with kilometer number in the display and no longer drives whether with gas lever or pedals.

It's brake sensitivity issue,
First, you can adjust the brake sensor distance. Use a 2mm Allen wrench to loosen the No. 1 screw, then unscrew the No. 2 screw a little, and then tighten the No. 1 screw.
You can also refer to this video (different ebike models):
Loosen the two sensor screws at the bottom of the brake handle, move the brake sensor inwards, and tighten the screws.
In addition, this phenomenon will also occur when starting the ebike while pressing the brake.
Release the brake and it goes away.
If the above problem is still not solved, you need to check whether the brake line has water in it or is damaged due to other problems.