Improve the speed of the site on Wordpress

Welcome.
Online store on WP. It is necessary to improve the speed of loading and operation of 4 pages (main, category, product and cart). Set up image compression, caching, deal with the long processing of the request when adding a product to the cart, change the number, etc. Solve other notices from verification services (google pagespeed insights, gtmetrix). Link to https://originalvaporizer.ru/ website
Write a few words about what you can help with and a rough fork of payment for work.