Even cheap bikes are being stolen by crackheads, it is not a deterrent.
I recently brought a 4500€ e-mountain bike, and my solutions are :
- a 20/20 motorcycle U-lock from Abus
- a 15/15 bike folding lock with a vibration alarm from Abus
- a LoRaWan GPS and movement/vibration tracker hidden in the bike
- only keeping it in my secure parking at work, inside my house or a few minutes at the grocery market.