Aren't factual statements used as a straw man arguments?

Not really, because a strawman is by definition a misrepresentation of an argument.
A more accurate version would be stating that the sun is a piece of burning coal.

What do you call it when someone who’s starving for attention says for example “The sun is a star” in a debate when no one in the group is debating that. They are addressing that skin cancer can be caused by being in the sun too much.

^^^^ “grasping at straws”.

No.

Factual statements in themselves are just that – statements based on fact.

In most cases “straw man” arguments involve misrepresentation of fact, as explained in this defininition :
https://effectiviology.com/straw-man-arguments-recognize-counter-use/

“A strawman is a fallacious argument that distorts an opposing stance in order to make it easier to attack. Essentially, the person using the strawman pretends to attack their opponent’s stance, while in reality they are actually attacking a distorted version of that stance, which their opponent doesn’t necessarily support.”

I’d tend to call that “stating the obvious.”

An example of a strawman might be: “Some people say that the sun is a different color when it rises than when it sets, and this means that global warming is real, but fortunately, I am here to tell you that THAT makes no sense…Listen up…”

I meant don’t some people try to use it (they’re just making noise) for the purpose of ’‘distorting an opposing stance in order to make it easier to attack eventhough it doesn’t even address the point tjhat they are debating.
So, what do you call it if someone says that ’‘The sun sets in the west’’ when the debate is whether the sun’s UV rays?
@Zaku ’‘The sun sets in the west’’ is stating the obvious but it is not stating the obvious regarding the skin cancer sun relationship.