Do rel=next and rel=prev still matter?
Google no longer uses rel=next and rel=prev to understand paginated series. The rules that do apply, from Google's ecommerce pagination guide, are that every page in a series has its own URL and its own canonical (never canonicalised to page 1), that content is not loaded only on click or scroll, and that shared titles across a series are acceptable.
What Google actually says
The ecommerce pagination guide states that Google no longer uses rel=next and rel=prev. Each page in a series should be reachable at a unique URL, carry a canonical that points at itself rather than at the first page, and load its items in the HTML rather than only after a click or scroll, which Googlebot does not perform.
The mistake that actually costs pages
Canonicalising page 2 onwards to page 1 tells Google the rest of the series does not exist, so whatever is listed on those pages is never indexed. That is the pagination fault worth fixing, and it is the one RankNexus flags.
Frequently asked
They do no harm. Removing them is tidying, not SEO.
Yes. Google says the same titles and descriptions across a paginated series are acceptable.
Grade your site against our 250-point AEO/GEO checklist and see exactly what to fix, free, no signup.