It is the sturdiest Abus foldable and Kryptonite Evolution. Hiplok would also be on my list of possible locks, but I do not like U-locks so much.

And as you said: if the attacker is dedicated enough, they will break it for sure.

But as I am working on implementing cryptography algorithms: every system can be broken, but the question is the trade-off between cost/time and gain. And my bike has definitely a really bad ratio compared to the bike with a thin string as lock, not connected to some solid object, right next to mine.