Being honest, at this poi t I would cautiously recommend filling a cupboard with a few staples because it's getting harder to find basics and it's going to get worse. People are clearing whole shelves of things like pasta sauce
.
Also go early in the morning. When supermarkets seem to be "out" of some things its often that they have stock but it just isn't on shelves. If you go early you have a much better chance of doing a "normal shop" before the shelves get cleared again.