KCD on Linux with Proton GE - "file not found"

[Greywander]

I'm trying to get KCD working on Linux; I managed to get it running with regular Proton, but was getting some weird graphical errors and performance was pretty bad. I saw someone recommend using a custom version of Proton by someone named GloriousEggroll, referred to as Proton GE. I downloaded and installed Proton GE, and I've confirmed that it works by running both Dark Souls 2 and Subnautica, but for some reason when I try to run KCD, I get a "file not found" error and it won't even start.

Obviously, this error message isn't helpful at all in figuring out what's actually going on. The fact that it's working with other games tells me that this is an issue with KCD specifically. I tried verifying my files and restarting my computer, but nothing seems to be working. If I'm missing a file, I have no idea what it is, and not every game seems to need it.

I was hoping someone here might have an answer for me, as I don't seem to have any leads on how to fix this.

[troylights]

It would help to know more about your system. I've had no issues at all running KCD and a bunch of other Windows games on Ubuntu 18.04 using standard Proton. KCD may have occasional bugs, but in over 40 hours I haven't had any major issues playing on mostly high settings (HD textures & sound) and averaging 60-70 fps outside towns. Rattay can have dips into the 30s, unfortunately, but I blame my CPU for that. Freesync makes towns bearable.

Ryzen 3 1300x @ 3.6GHz, AMD RX 580 8 GB, & 16 GB DDR4 3200 RAM. 1080p 144Hz Acer Freesync monitor.
Ubuntu 18.04.3, kernel 5.0.0-37-lowlatency, Mesa 19.3 (Valve ACO PPA)
I also use Feral Interactive's Gamemode (PPA for Ubuntu) to boost system performance while a game is running.

I apologize for not answering the question asked. Could you be more specific about the issue(s) you had with regular Proton running this game and some info about your system?

[Greywander]

Here's some of the glitches I got under regular Proton:

The graphical glitches are a bit difficult to describe. When looking in specific directions, I'd see what I supposed kind of looked a bit like a waveform (a straight line with random spikes rising from it) that would have a strange color and was drawn on top of everything else (you could see it through walls and stuff). It gave the impression of perhaps being something in the far distance (e.g. if I walked around), just drawn on top of everything. The shape didn't move or change shape unless I changed the angle I was looking at. It would show up consistently if I looked in the same direction.

When looking around, I'd also see random garbage frequently, probably the same glitch as above. As mentioned, looking at the same angle would show a static graphical anomaly, but changing the direction I was looking would cause it to change shape, so looking around would create a lot of random garbage.

Another graphical glitch would sometimes cause a sort of hallway effect, where whatever I was looking at would be projected onto a triangle that gave the impression of perspective. You know when you get to an out-of-bounds area in a game where it doesn't redraw an area, so if something passes over that area it leaves a permanent after image? That's what it looked like.

FPS was also very low. I don't recall the specifics, but IIRC the only time I got anything approaching 30 FPS was when looking at the ground, on low settings. The rest of the time was 10-20 FPS.

My CPU was also running very hot, ~50 C, and all four cores were being used heavily. As I type this, my CPU is only running at around 25 C. It's understandable it would run hotter while gaming, but this seems a bit too hot.

Here's my system info:

Operating System: Linux Mint 18.3 Cinnamon 64-bit
Cinnamon Version: 3.6.7
Linux Kernel: 4.15.0-72-generic
Processor: Intel(C) Core(TM) i5-2500K CPU @3.30GHz x 4
Memory: 19.6 GiB
Hard Drives: 1944.6 GB
Graphics: NVIDIA Corporation GM204 [GeForce GTX 970]

And yes, I'm long overdue for an upgrade. Just gotta scrape some cash together.