Short answer: WordPress is not the reason a site automatically fails to rank. The issue is usually a page, technical or intent problem that has not been isolated.
Check the owner page
Give each important search intent one clear owner URL. If several pages promise the same service, Google and visitors receive mixed signals. Consolidate overlapping pages before creating more of them.
Check indexation before judging rankings
A page cannot rank normally if Google cannot crawl or index the intended version. Check the HTTP response, canonical, robots directives, internal links and URL Inspection data. Google explains how preferred versions work in its canonicalisation documentation.
Check rendering and the offer
The page must load reliably and make its service clear. A theme, builder or plugin stack can introduce unnecessary scripts or a fragile customer experience, but replacing a plugin without evidence may change nothing. Inspect the exact page, then decide whether a targeted repair or a WordPress SEO audit is needed.
Change one hypothesis at a time
Record the page, query, hypothesis and expected signal. Do not change the URL, title, content and theme at once if you need to learn what helped.