YO Stadia Team
I try to play Elder Scroll with Stadia but it is almost not posible there are so big lags, frezees and glitch that is impossible to play. For example Cyberpunk or Hitman works great I think Hitman is the best quality ever with Stadia. I think there is some problem with Online games Single player games works better than Online.
Seems odd since ESO works perfect for me. I've even played it using wifi hotspot on 4G from my phone far out in in the middle of nowhere without the problems you are describing.
Keep using the Stadia feedback. Perhaps there isn't enough stadia instances that runs ESO near your location.
Elder scrolls has connection issues regardless of how it played. though on regular pc, meaning not streaming its less noticeable unless cyrodil or w.e its called. but thats on bethesadas server side fault, for being old and hamsters are dieing
One problem could also be that ESO is running on 30 FPS usually on Stadia, so this can also cause some problems in regards of lags, etc.
Usually the game is working fine for me though, but I don't do dungeons or raids on Stadia as I have the PC version anyway, so I can't tell if the problems you encountered are because of this.