Core Web Vitals Work - Mobile & Desktop / Google Search Console

We are a global website and considering updating our existing Wordpress website to meet all the elements of core web vitals. Our current website runs on the latest Newspaper theme but has issues with CLS and LCP on core web vitals. Our Google Search ranking has been impacted greatly with poor urls.

1. The current sitemap in Google Search Console is too large - hence the core vitals is reviewing over 16,000 pages - can we just ensure the pages that matter are indexed - the news pages - if we can limit it to just the pages for the last 2-3 years that would be even better.

2. The Desktop scores are good but none are passing

3. Mobile scores need improving - none are currently passing

4. If there are sections on the website that are slowing down pages loads, let me know so we can consider removing / modifying

As discussed, payment to be deferred until after the Google review of 28 days.