Thanks Matt!

I have enabled the quicknav's setting _isEnableNextOnCompletion. When I tested it, the next button does not allow to move forward, which is expected. Additionally, I was looking for a pop-up with a message mentioning what action the user has to take to complete the page.

I found this plugin: https://github.com/cgkineo/adapt-pageIncompletePrompt. This helps to show a message when the page is not completed, also allows the user to move forward based on their preference.