bikebikebike

I will use a flimsy cable just to prevent hop on and ride offs while I pee or get coffee, but not for more than 5 min.
but a D lock for anything more. That's flat gambling. Not blaming , but really, you gambled and lost.
A pro thief is a pro, and eyeballs are the only defense. Locks that are portable, just delay or distract them.
Most cables and locks are made of butter. Bike racks are a buffet.

I have adapted a hand cart to tote my 20"ers, modeling after the Brompton SIDEWINDER. for any portage over a few yards,
because all folded foldies roll like a turd in their native state, regardless of what they claim.
If anyone objects to the bike on the bus/train, I use a cover and call it luggage or my Personal mobility device,
and make up some malarkey about being an elderly cripple or something equally pathetically offensive if challenged.

I would no more lock a bike on the street or public spot than leave my wallet on the table.
If I have to do that, I ride a bike that cost less than the lock.