How to Check Your Site's Performance Using Chrome Devtools - Lighthouse
Look for optimizations like heavy or unused scripts that can be removed
In Chrome browser, open Network Console by pressing CTRL+SHIFT+C
then click the >> right arrows to see more tabs
select Lighthouse
go to site you want to check (I am checking forbes.com) and then click the blue button that says Generate Report. Note you can select Desktop or Mobile
Chrome will run through the scenarios as a desktop browser and report the findings and performance.
Look through the recommendations and then decide which optimizations to make. For example if there is unused javascript, it will tell you which ones they are and how much “savings” of load time you will see if you “removed unused javascript.”