Website Upgrades and Redesigning

1- install a new product filter plugin
2- Install the Return/refund plugin
3- install cash back reward plugin
4- add sub-category pictures to my menu
5- redesign my home page
6- update all existing plugins and remove unused plugins
7- clean website codes and make the website faster because it's very slow now

I want to Test all new plugins on a separate website with my products to ensure the functionality