A Norwegian insurance company did a map of all the places bikes were stolen in Norway last year. Every stolen bike happened in a large town or city (90% in large cities). I always buy food in small towns and villages and if I’m in a big city I will take my bike in to the supermarket. You really don’t need to carry a big lock with you.
At night if your bike is next to your tent It won’t get stolen unless you camp in a park in a city (which is illegal anyway).

I have in the past taken a hiplock to tie the bike up when food shopping. https://hiplok.com/product/zlokcombo1/

For something a bit stronger and still very compact and light:
https://www.tradeinn.com/bikeinn/no/ottolock-las-av-kabelbinder-cinch/137889470/p?utm_source=google_products&utm_medium=merchant&id_producte=12076404&country=no&gclid=Cj0KCQjw4NujBhC5ARIsAF4Iv6c65C0Hp8Apo44VKJM0uJhOFSFuxsLHqZbnE4hKkPzGfG-FLDru9OQaAg38EALw_wcB&gclsrc=aw.ds