Are you by chance using a laptop with 2 graphics cards? That's a fairly common issue because in that situation you sometimes have to indicate with environment variables that certain programs should use the dedicated GPU rather than the integrated GPU which is generally a lot weaker.
GNU/Linux Gaming on Kbin
A community for gaming on the GNU/Linux distros.
Overwatch 2 via Lutris - Runs but with significant stuttering making it difficult to play
Haven't played 2, for 1 was notorious for this due to shader compilation. If you stick with it for like an hour it should clear. You can tell if this is the issue if you go into the training mode and it stutters the first time you fire an ability, but not subsequent times.
Diablo 4 via Lutris - Cannot run due to "Graphics Initialization failed" error
Quick Google suggests try downgrading VKD3D through Lutris options.
Yeah, I think it may be a shader compilation issue for OW2 but I saw reports of people not suffering this or being able to fix it so I hoped there had been progress.
I did try downgrading VKD3D, as I mentioned in my post, but this didn't help with D4.
D4 works perfectly for me, not sure what the issue would be. I have an AMD card, are you on Nvidia?
Nope, not Nvidia, AMD Radeon RX 6700XT
Out of curiosity, have you tried Bottles yet? This is what I use, and it works just fine for Diablo 4. I know that Lutris and Bottles both use Wine under the hood (although Bottles has some customization on top as far as I understand?) but perhaps the defaults is what makes the difference.
If you still have D4 downloaded, when you install the Blizzard launcher into Bottles you should be able to copy (or move) the files from where Lutris is storing them over to the new directory, and then Blizzard's launcher has a "Find installed games" option somewhere that will then make it recognized as downloaded.
Since you're on Ubuntu which doesn't have Flatpak support by default, you'd need to setup Flatpak for Ubuntu and then you'll be able to install Bottles from Flathub if that is something you were interested in. On the upside, it supposedly has really good compatibility for regular Windows (non-game) applications as well, though I've yet to try that part out.
Okay, this helped a lot. Got D4 working (noticeably lower graphic quality, but completely smooth fps and very playable), and also massively reduced the stuttering for OW2.
For any future readers, I definitely recommend Bottles over Lutris or standard Wine for Battle.net and related games.
Thank you very much for the suggestion!
Thanks for this, will give it a try!
For Diablo 4, inside Lutris under the settings for Battlenet change the VKD3D 2.9 to version 2.8
Edit: sorry I see you already tried that
Did you try Proton-GE/Wine-GE? Download ProtonUp-Qt and use it to try different proton/wine versions
ProtonUp-Qt:
https://flathub.org/apps/net.davidotek.pupgui2
For Lutris:
https://github.com/GloriousEggroll/wine-ge-custom/releases
For Steam:
https://github.com/GloriousEggroll/proton-ge-custom/releases