The Tip of the Night for September 1, 2019 discussed Fiddler Cap which is a simplified version of Fiddler - the web traffic inspection tool. The full version is available for download here on the Telerik site.
If you click on the Timeline tab, Fiddler will generate a graphic that shows how long each of the selected web page elements takes to load. A red X on this graph will indicate where a connection was lost.
If you click on the Statistics tab, you'll see which elements of a web page take up the most bytes, and how many requests are needed to load the page.