is conducting a website audit still worth the effort?

Yes, but not the kind where a tool spits out 300 "issues" and you try to fix all of them. Most of those are noise. The parts that still pay off: pages Google isn't indexing (Search Console's Pages report tells you why), broken internal links and redirect chains, duplicate or missing titles on pages that matter, and templates that are slow on mobile. That's an afternoon, not a month. Do it every quarter and after any redesign or migration, which is where sites usually break.