I have a Diablo 4 addiction. It runs surprisingly well on my Deck. Only problem is it requires the internet, so I can't play it anywhere outside of the house.
I'm baffled by how poorly Diablo 4 handles "mediocre" connections. I have been using T-Mobile Home Internet for a while and I'm even able to stream GeForce Now reasonably well, but I run into lag spikes on Diablo 4.
I don't think it's a network problem. I think Diablo has a memory leak that causes issues that are especially noticeable on the Steam Deck. I've heard it's getting patched out soon, but not sure where I got that info from. One of my Discord friends I think...
I can pretty well track my performance issues to network performance. If I play in the morning when TMHI is performing better I don't see any issues, while in the evening when the network is congested I run into lag.
I know I'll probably pick it up eventually, but I wanted to wait and see if Blizzard ruined the game through the early patches. Diablo 3 eventually turned out good, but playing during the launch year was a rough experience.
Besides, if I wait long enough there's now hope they'll release it on steam.
I was actually quite impressed with how Blizzard revived D3 with Reaper of Souls and its Item 2.0. They had some really bold and new (for the time) ideas and it worked.
But that was Blizzard of old and I have very little faith that they're able to pull the same revival off on D4. The campaign was interesting, sort of, but beyond that: an awkward compromise between D2 and D3, and without the panache of either.