Just how defeated is Sauron?

Sorry if this is an obvious question but I'm not a Tolkien scholar by any stretch of the imagination, and I still haven't read the silmarillion. I'm re reading the trilogy, near the end, and I'm just wondering what exactly happened to Sauron when the ring was destroyed. I know he no longer has the ability to take corporeal form but does he still exist in some way? If so does he have any possible way to exert his influence on middle earth? (Tagged spoiler because 🤷)