Pagespeed Optimization

We want better pagespeed score for our Multivendor website particularly for mobile.
Our main aim to do this is so we can increase our search rankings as Google looks at factors like LCP and CLS, secondly it is to improve user experience on the site (fast loading times etc). We currently use Webp images but it is not enough.
Main outcome in the end should be a better Google Pagespeed/Lighthouse score (At the very
least 70+) and at the minimum (B+ ranking for GTMetrix)
Feel free to message me privately if you have previous experience in this matter.