WordPress Site Speed Optimization

My WordPress-based store uses Ecwid for the shopping cart and it has become noticeably sluggish on both mobile and desktop. The two areas that matter most to me are the homepage and the product / catalog pages; improving their load times and Core Web Vitals is the priority... (Budget: $10 - $30 USD, Jobs: CSS, Frontend Development, HTML, Performance Tuning, PHP, Web Development, Website Optimization, WordPress)