Should I cut contact or have a final conversation?

When someone initially shows a lot of interest in you, but then suddenly starts acting cold and distant, it's evident that something has changed between you. Despite attempts to address the issue, they insist that everything is fine. However, it becomes increasingly difficult to ignore the obvious shift. At this point, you may wonder whether to go no contact or have a final conversation with them to express your concerns. If they refuse to communicate, it may be best to end contact, as pretending that everything is fine becomes unsustainable. If you decide to cut contact, does it equate to a breakup?
Will the other person eventually return? If they don't, and you were the one to suggest cutting contact, is it appropriate to reach out again in the future to gauge their interest? If so, how long should you wait before doing so?