If you highlight the whole page, you highlighted nothing. Priorities work the same.

Emphasis only exists in contrast, so marking everything as important removes the category entirely. A list where every item is urgent gives no instruction, so you choose by mood or by whatever is loudest. Deciding what matters means deciding what does not.

Take your current list and pick the one thing that would make the rest easier or less necessary. Do that first, before anything else touches the day. Let the others be genuinely second, which is uncomfortable and is the entire point.