The old advice was to canonicalize pages 2, 3 and 4 back to page 1, but Google has said it can handle pagination on its own, so a lot of people now self-reference each page instead. The trouble with pointing everything at page 1 is that products linked only from deeper pages can fall out of the index and lose their signals. The case for page 1 is that it keeps near-duplicate pages from competing with each other.
I lean toward self-referencing canonicals, as long as each page shows a real product set. For thin, filter-style pages where page 2 is just more of the same, I'd noindex them instead.
To judge which approach is working, compare index coverage in Search Console against organic landing sessions in GA4, not just rankings. Which signal are you using?