I used to play on a GPD Win 2 and it was more than playable on lower settings. Given that the Steam deck is more powerful, I don't see it not being able to handle the game.
A friend of mine does - he says it works "slick". He does have a really good ISP, which he says makes all the difference. I have to take his word for it, as my only available connection is satellite, and I wouldn't buy anything from steam, or use theur service.
If you close the launcher window ESO runs amazingly well on the deck. Outside of stutter loading assets in heavily populated areas it generally hits 60fps for overland dungeons and even trials.
ESO plays flawlessly on the Steam Deck. I got one at the beginning of the year and I have encountered no problem playing the game on it. As Twyst suggested, if you close the launcher, it delivers a really smooth framerate. I prefer to play on my PC, of course, but for dailies, writs, overland, it's great. The Steam Deck is a game-changer in many ways. I love mine.
Ngl, but I think it'd be really neato to play ESO on the Deck, but at the same time, getting to meet up with people at an ESO convention and getting to all play together in person (I miss LAN parties, so that's something close to it in concept).
One day I'll get one and most likely give ESO a shot on it.