Abus alarm lock is my choice. You need to be very skillful at lock picking and the motion sensor will trigger an alarm if the appropriate key is not inserted properly. I wouldn’t trust my nice bike to anything else. Hope it helps!
I am considering this one: https://www.amazon.com/dp/B077P6NN23/
Although I realize it only buys you not much time: https://www.youtube.com/watch?v=v46druOo7UM
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I also own a u-lock ( https://www.abus.com/eng/Mobile-Security/Bike-Safety-and-Security/Locks/ABUS-uGrip ) and chain lock ( https://www.rei.com/product/855066/kryptonite-new-york-1210-chain-lock ) , but find myself not using my folding bike as much when I know I need to carry them around https://i.imgur.com/tQ71kRS.jpg