Which bike lock?

[Yellwo]

I never fully leave leave my bike anywhere but I’m looking for a lock for things like leaving it for five minutes to nip into a cafe to buy a drink or leaving it out of reach but in sight like at the side of a running track while I run. Situations where I'd have to be ridiculously unlucky to have it nicked before I could go 'oi, that's mine' but I don't want to leave it unsecured.

I'm getting sucked into thinking I should buy something better than a ten quid combination lock by reviews online but really, for what I want it for, is there any reason to buy a better lock?

Have you seen the pictures of blokes with angle grinders? They will cut anything.

I have an expensive gold rated lock. I tell myself it acts as a deterrent as while they can be cut it takes a lot longer than one of the cheap ones.

They are heavy though.

However, I have a supremely stealable desirable bike that has to be left in a bike shed at work unfortunately so I feel my theft risk is high.

a small u lock would be good. but for your use case a Abus cableflex could be a good option

I have a Kryptonite D lock with a flex-y thingy, it works well.

As PP says, though, somebody with an angle grinder can and will get through them, if they really want to.

If it is in sight any lock would do.
If you are out of sight all bets are off tbh
If im going anywhere where my bike is going to be left for a significant amount of time I will always use my cheapest , not worth stealing bike. If i know I can keep an eye on things or it is in a secure place , only then will i use my decent and more expensive bikes.