Resolve GSC Indexing Errors

My site is showing indexing errors in Google Search Console and many pages are simply not making it into the index. I need a specialist to investigate why Google is skipping these URLs, correct the underlying... (Budget: £10 - £20 GBP, Jobs: Content Management System (CMS), SEO, Technical Support, Web Crawling, Web Development, Web Security, Web Testing, Website Management, Website Optimization, Website Testing)