As u can see my ebike looks like a motorcycle and has the same steering lock they do I just turn the key to the lock position and it lock the bars in 1 spot and with my app I can lockout the motor as well
I use this one: https://amzn.to/2H85KEl. I have it underneath the seat, and it was a very tight fit (I had to remove the back cover even). No way anyone can remove it. It works great! Gives me peace of mind knowing that if anybody messes with my bike in anyway, that alarm is going to make it very obvious. And people dont expect an alarm on a bike, so it really startles.