I currently live in a country where supplies are not as robust as the UK/Ireland, despite being very developed. There are often big gaps on shelves or products already out of date on sale. But it is also a country where the majority of people drink bottled water, most milk is UHT, they sell things like confit duck and coq au vin in tins, etc.
So I tend to eat as much fresh as possible in general - fruit and veg, meat and fish, milk, cream, cheese, eggs…
I always have some store cupboard items for normal use…rice, pasta, couscous, tinned tomatoes, tinned beans, tinned corn, frozen veg and oven chips etc.
I also have some conveniences like a bottle of UHT milk in cupboard for returns from travels(shops have more limited opening hours than home), box of smash type mashed potato (add real milk and lots of butter and it’s perfectly fine and much easier when life is mad busy), the odd ready meal (for ovens as I don’t have a microwave). And some nice ribs like the confit duck as a treat.
But I also do a lot of batch cooking because I am so busy - so buy all the fresh things, and make stews, curries, spag Bol, chilli etc sauces (using fresh ingredients and often involving slow cooking g for hours and maybe reducing down a half bottle of wine in a spag Bol etc) to freeze in 1 person portions. Or I buy a chicken and portion it up, make stock with the carcass, roast some for today, but chop up the breast and freeze and make greek lemon herb marinade (from fresh lemons, fresh herbs, fresh garlic and local honey) to pour over the thighs and freeze, for other easy dinners.
I have a 2 drawer plastic unit in a cupboard with my “stockpile” - which is all things I eat anyway but maybe a tin of olives that can go in a casserole but would be good to add variety and can be eaten straight from the can. Or a couple of jars of pasta and curry sauce for emergencies but that can be helpful in very busy weeks - when I don’t have time for onion, garlic, ginger, coconut milk, spices….versions.
I generally only buy what I will use in some form - and rotate what’s there. Sometimes it means experimenting with things (mostly successfully…but I can eat 1 strange meal once in a while…so I try to limit real experiments to once in a while). And usually it’s adding those as ingredients to other fresh things, rather than a full store cupboard meal of tinned potatoes, tinned mushrooms, tinned corned beef and a glass of UHT milk. (I don’t have corned beef or hot dogs…but will buy a tin of cockles or mussels on occasions for a couple of different pasta or paella dishes when it’s not shellfish season).
My examples are all relatively normal and relatively cheap here. Baked beans and spaghetti hoops are more expensive than many things we’d consider exotic at home but are good basics here.