We’ve used chrome tools, lighthouse / pagespeed insights, firefox developer tools, gmetrix and similar to get an overview of initial page load issues that can affect google bots and users visiting your web site. Yet there is more to user experience of a page after loading that can be issues to consider resolving for similar issues.
Here is a short video from the Google Search team about using the Chrome tools to view speed and other issues after a page has loaded and user interactions could show issues to fix for better performance.
Not all web pages have these extra interactions, however it may be worth checking to see if clicks or hover issues show unforeseen speed issues. If your page has click to add, or even hover to show a menu, it may be worth understanding the performance of such functionality.