Using Matomo's page performance metrics to detect network problems

Hi all,

I have a couple of questions regarding the page performance tracking in Matomo.

[A little backstory]
The problem we are facing now is some of our customers in one site (an intranet-based enterprise web application almost always used by desktop users) are complaining about rare and intermittent slowness and sluggish performance. When we analyze the application server logs, the numbers seem acceptable, so our application or database server performance is not the source of the problem. This web application doesn’t heavily use JavaScript (written using jQuery and no fancy new technology or SPA frameworks), so the only thing we can blame now is the clients network infrastructure. We want to know if Matomo’s page performance tracking can help us.

[Questions]
Is there a way to measure how much time did the browser spend before a request was delivered to the server? Does “network time” measure exactly this metric? Does “transfer time” metric show any slow network download speed? And when the goal is to prove there is a network problem, how reliable Matomo’s page performance measurement is in comparison to browsers’ developer tools or addons such as Performance-Bookmarklet (https://github.com/micmro/performance-bookmarklet)?