Where plugins help

They are useful for titles, descriptions, open graph fields, robots controls, and some schema defaults.

Where they stop

They cannot clean a slow template, weak internal links, accidental duplicates, broken redirects, poor product data, or JavaScript output that search engines cannot read well.

What matters

Crawl paths, canonical URLs, robots behavior, sitemap output, product schema, page speed, content hierarchy, and redirect behavior need to be checked together.