Have you ever dealt with the performance problems on front end and how did you fix it?

I have dealt with performance problems while working on a specific project.
It is a large-scale startup project based on React.js library.
As the project scale grew, the loading and action reacting speed became slow and it laid out a very important problem for releasing the project.
Firstly, I focused on refactoring the code for fixing the unnecessary rendering of components.
So I made useEffect hooks to separate to have the only necessary dependencies and made the components to PureComponents as possible.
Next, I reduced the bundle size of the project using the webpack bundle analyzer plugin.
Finally, the speed was improved by 70%.

Have you had the other experience related with performance problem?