Website speed optimization, 90+ on https://pagespeed.web.dev/ for both mobile and desktop required

I need my WordPress site consistently scoring 90 or higher on Google PageSpeed Insights for both mobile and desktop. At the moment the pages load noticeably slower than they should, and the Core Web Vitals warnings are beginning to affect search visibility as well as user experience... (Budget: $30 - $250 NZD, Jobs: CSS, HTML, PHP, SEO, Web Design, Web Development, Website Optimization, WordPress)