I agree that this arrows are not a good UX choice.
A better visual indicator that make clear the meta boxes can be moved/rearranged can be the classic “drag and drop” icon, that is different from the arrows used to open/close the box. Also, the position for this icon can be different as well, maybe on the left side, before the box title.
When a new feature is added, it’s important to take time to think where this option can be to offer the best user experience.
