Rocket_SEO's point about deciding per page from GSC is the part most of these threads skip. "Update content or build links" isn't really answerable until you know which one the page is short on.
The split I use: pull the query report for that URL and look at where it sits. If it's ranking 8 to 20 with impressions and almost no clicks, that's usually intent or the title, and a rewrite moves it. If it's stuck outside the top 30 while thinner pages sit above it, no amount of refreshing tends to help, that's a competitiveness problem and links are the lever.
The one that catches people is the third case, where the page barely has impressions at all. Updating that is just rewriting something nobody was shown.