The substance of all of creation is a constant, renewing command from HKBH. This is the underlying energy-matter of the universe.
Now, that is when we discuss יש itself. However, the term בריאה refers to inventing the concept of something, which is why it can refer to חושך even though in practice חושך wasn’t ‘built’ but rather left as the other side of the אור scale.
When we discuss an item we are discussing its form, its identifying qualities or personality. We don’t really pay attention to its makeup. Although my internal molecules change over within a given time it wouldn’t occur to you to consider me a ‘different’ person.
And so, the world was formed once and for all while the underlying substance does depend on a constant renewal.
My reference to electronics is that we are already used to the idea of character on a screen being referred to as an entity, all while we know good and well that its substance existence is constantly given forth by the local machine.