There is a bug report with some discussion here: https://github.com/ValveSoftware/steam-for-linux/issues/8076

My shot-in-the-dark guess is that you were unlucky, and hit a bug in the game. It might be something triggered by a particular detail in your game state which would explain why you didn’t have problems earlier. You could test that by starting a new character, and testing whether you see the same problem.

If I were in your position and feeling motivated I would submit a bug report to Bethesda with as much detail as I could manage.

I think one of the most impactful choices in my last build was choosing a fast SSD. Not all SSDs are the same! Nowadays you can get NVMe drives that operate over PCIe instead of SATA which provide much higher throughput.

You can either get an M.2 form factor that plugs into a special socket on the motherboard and takes up minimal space, or a PCI card that plugs into the same type of slot as a graphics card. (Note that some M.2 drives / sockets are SATA, not NVMe, so watch out for that distinction.)

There is also some difference between NVMe implementations depending on which PCIe version they support. And you’ll want a motherboard that implements the same PCIe version. This applies to both M.2 and PCIe SSDs.

This stuff might be old enough that you’ve already encountered it. But it was new to me when I built my last PC in 2020. Other than that building was pretty much as I remembered from previous decades.

Oh, I forgot to do my fanboy plug. I’ve had the easiest time setting up Proton dependencies on NixOS. It unifies configuration with package management, so the Steam configuration module can reference your installed hardware, and load the appropriate graphics packages automatically.

Basically you opt into unfree packages, and put programs.steam.enable = true in your NixOS config, and that’s it.

I don’t know what the issue is; but something to try if you haven’t already is to go through the setup instructions on the Arch Wiki, paying special attention to making sure that you have the correct 32-bit graphics dependencies installed.

I believe your last Linux experience in 2015 predates DXVK which has been transformative for Linux gaming. Wine used to have to implement its own DirectX replacement which necessarily lagged behind Microsoft’s implementation, and IIUC didn’t get the same level of hardware acceleration due to missing out on DirectX acceleration built into graphics cards.

Now DXVK acts as a compatibility bridge between DirectX and Vulkan. Vulkan is cross-platform, does generally the same stuff that DirectX does, and graphics cards have hardware acceleration for Vulkan calls the same way they do for DirectX calls. So game performance on Linux typically meets or exceeds performance on Windows, and you can play games using the latest DirectX version without waiting for some poor dev to reimplement it.

If you are using Steam with Proton, Lutris, or really any Wine gaming these days you are using DXVK. It’s easy to take for granted. But I remember the night-and-day difference it made.

Instead of trying to get Steam to write outside of its sandbox, I would configure the OS to search Steam’s files for application launchers.

Your system searches “data” directories for directories called applications, and loads .desktop files from there. You can customize locations for data directories using the XDG_DATA_DIRS environment variable. See https://unix.stackexchange.com/a/492878

In this case you want to set XDG_DATA_DIRS to include ~/.var/app/com.valvesoftware.Steam/.local/share because that is the parent of the applications directory.

I think you’ll want to include the default data dirs so you don’t lose your other launchers. So something like,

export XDG_DATA_DIRS="/usr/local/share/:/usr/share/:$HOME/.var/app/com.valvesoftware.Steam/.local/share"

If I’m understanding the spec correctly you don’t need to include ~/.local/share because that is the default path for XDG_DATA_HOME which is always searched, and XDG_DATA_DIRS specifies additional paths to search.