Eso has been unplayable (as said by other players) for years, and yet I still play it. It's been hot, laggy mess for a long time now. Probably due to limitations caused by last gen consoles preventing the devs from relieving the server load lest they make last gen consoles unplayable.
I play on PC and never have a problem with lag (but depends on what you're doing too). The only time I have a problem is when one of my addons decides to mess up- which is rare... but does happen from time to time. Open world questing, world bosses, delves, dungeons... no problem. Dolmens, especially Alik'r, yeah it can get laggy when there are a lot of players around. PVP... I have no idea.
If you are still experiencing latency issues, I would recommend following the steps in this article to see if they can help resolve them. Please let us know how it goes!