If no traffic or links, but the content serves a purpose for visitors (builds trust, establishs credibility/authority), set to noindex so visitors can still view the page, but Google won't waste any crawl budget or space in its index. If no traffic or links and the content doesn't really serve any purpose for visitors, delete it. If no traffic, but links point to the page and the content serves a purpose for visitors, optimize it. If no traffic and the content does not serve a purpose for visitors, but links point to the page, redirect to a similar page. If traffic and links, but the content does not serve a purpose for visitors, redirect to a similar page. If traffic, links, and the content does serve a purpose for visitors, optimize it.