Speed up the loading of the report on the site, eliminate bugs with the table

The site is written in php, mySQL database, extjs tables, graphs (I dont remember).
It is necessary:
1. Speed up page loading
2. Make it possible to select all rows at a time

If you are interested in this task and you are ready to study the problem more deeply - I will send you access to the working report, answer questions.

Suggestions are welcome, up to and including a code change.
But due to the fact that the site is already used by people, it is important to solve the problem with speed quickly.