So you don't know what figures of speech are? ...And even today we still say the sun rises and goes down, or sets, when we know it doesn't actually do so. It's not literal; it's about perspective.
Today we know that the earth both rotates and revolves around the sun; therefore, whenever we speak of "sunrise" or "sunset" we are using idiomatic expressions. However, there is no reason to suppose that the author of Ecclesiastes 1:5 intended it to be taken as an "idiomatic expression" when he referred to the sun rising or setting. A phrase is to be taken as an idiomatic expression only when the person speaking it knows it to be such, but the geocentric model was the commonly held belief among all ancient peoples, including the Hebrews, and their scriptures reflect this belief.
There is nothing in the Bible to indicate that the earth rotates or revolves around the sun. Where did you get the idea that the earth rotates and revolves around the sun? You didn't get it from scripture, that's for sure.
Furthermore, based on your line of argument, one could just as reasonably assert that the Genesis accounts of creation and the flood are filled with "figures of speech" (e.g. "days" meaning eons instead of literal 24 hour periods, etc.).
Why do you assume "world" means "earth"?
2 Samuel 22:16, Psalms 18:15 and Proverbs 8:26 show that "earth" and "world" are effectively synonyms with regard to Psalm 93:1 and 1 Chronicles 16:30.
Also, Psalm 104:5 is about the foundations not being moved.
Let's take a look at Psalm 104:5:
You who laid the foundations of the earth,
So that it should not be moved forever...
"Foundations" is plural; "it" is singular. "It" refers to the singular earth, not to the plural foundations.