In August 2014 Google made HTTPS "a very lightweight signal", "affecting fewer than 1% of global queries." Today's page experience documentation lists secure serving as a good practice but says "beyond Core Web Vitals, other page experience aspects don't directly help your website rank higher": HTTPS is not a direct factor now. Serve it anyway: Chrome 1 has labeled HTTP pages "Not secure" since version 68 (2018), many web APIs need a secure context, and Let's Encrypt 1,144 is free (Securing with HTTPS). When migrating, 301-redirect every HTTP URL to its HTTPS twin.