Let me repeat an earlier post I made. There is only 1 bicycle lock on the market currently that I know of that can be carried practically, and be angle grinder proof, and that lock is the Hiplock D1000, which includes any chain, any other D lock, any folding lock, any cable, etc. There is another lock that is also angle grinder proof but the thing was so huge it is highly impractical to carry it on a bike.
It strikes me that a lot of testing/evaluation of locks is done by people who have never stolen anything.
I really laugh at the idea of an angle-grinder proof lock. Such a thing doesn't exist. It is where you leave your bike and how you lock it that matters. If someone wants your bike they will get it eventually but if you can put them off and go for the next one, you have a chance that you'll keep yours.
I used to know a cyclist who owned a Bike Friday. It was stolen from the middle of Manchester. The thieves turned up with hi vis jackets in a van, cut the Sheffield stand and removed all the bikes in one go. Hers was probably the same price as all the others on the rack. They didn't care. Probably all got weighed in.
My Oxford D-lock was about £40 IIRC. 18mm shackle, so too thick to cut with a bolt cropper. I doubt a thief would care or notice the difference between that and a D lock that cost 8 times as much.
Just get the lock that keeps your insurance happy, and lock up somewhere sensible. Frankly, it would be easier and more likely for me to get beaten up while unlocking my bike, or for me just to get jumped while I was riding it somewhere.