Use Behaviour Flow from Google Analytics to redesign the website navigation menu

I am working on a big project to redesign the navigation menu of a website. There is a similar question that helped me a lot, but I have the feel my case is somehow different.

The website is not an e-shop or something with a CTA, so I cannot evaluate the starting to ending point of the flow. It is a dashboard that users spend a lot of time from one page to another, with a few pages on the main navigation bar and different left and right sidebars for each page. In total, more than 40-50 different links.

My aim is to identify the patterns from Behaviour Flow (or other stats) on Google Analytics and regroup links to reconstruct both the navigation menu and sidebar links.

So, I am looking for tutorials, similar studies, academic papers and case studies that I could use as a starting point.