Quake (2310): Online Multiplayer doesn't work

Compatibility Report

• Name of the game with compatibility issues: Quake
• Steam AppID of the game: 2310

System Information

• GPU: NVIDIA GeForce GTX1650

• Driver/LLVM version: nvidia 510.54

• Kernel version: 5.15.0-18-generic

• Links to full system information reports:
  https://pastebin.com/5bBkLKCq
  https://gist.github.com/virnik0/7e2ed791752e9437f8fae12ed90baf8c
  https://gist.github.com/virnik0/237df0bed83bab3d387eeae472af6da5
  mainframe.pdf

• Proton version: 6.3-8, 7.0-1, Experimental

I confirm:

• [* ] that I haven't found an existing compatibility report for this game.
• [ *] that I have checked whether there are updates for my system available.

Launch Options used:
__GL_SHADER_DISK_CACHE=1 __GL_THREADED_OPTIMIZATION=1 PROTON_NO_GLSL=1 PROTON_ENABLE_NVAPI=1 VSYNC=0 PROTON_NO_ESYNC=1 DXVK_ASYNC=1 PROTON_LOG=1 VK_ICD_FILENAMES=/usr/share/vulkan/icd.d/nvidia_icd.json gamemoderun %command% -skipmovies
steam-2310.log

Symptoms

Multiplayer Online doesn't work. The game fails to show response time to listed lobbies.
If I try to connect to any multiplayer lobby, I am being told that the lobby doesn't exist.
I can't create new multiplayer (online) lobby. Searching for a match never finds anything.

Reproduction

a) Run the game
b) Enter Multiplayer-> Online, try to either create a new game or join existing available games.

I have tried setting Win version to Win7:
protontricks 2310 win7

I have tried to wipe Proton runtime directory and restart steam/game:
rm -rf /home/virnik/.local/share/Steam/steamapps/compatdata/2310

I also wiped runtime directory before switching Proton runtime version.

I made sure that my RTC is set as close to time source as possible

But I also tried syncing directly with CZ/Google time source, but the difference was really mediocre and wouldn't have any real impact:

virnik@Mainframe:~$ sudo ntpdate tik.cesnet.cz
18 Feb 08:44:08 ntpdate[630222]: adjust time server 195.113.144.201 offset +0.001051 sec
virnik@Mainframe:~$ sudo ntpdate time.google.com
18 Feb 08:44:22 ntpdate[632537]: adjust time server 216.239.35.8 offset -0.000462 sec

My local time source status:

virnik@ap-voyager:~$ ntpq -pn
     remote           refid      st t when poll reach   delay   offset  jitter
==============================================================================
 10.43.16.1      .INIT.          16 u    - 1024    0    0.000    0.000   0.000
+10.43.17.1      195.113.144.201  2 u  520 1024  377    1.976    2.690   2.248
-10.43.18.1      195.113.144.201  2 u  405 1024  377    3.336    0.624   1.412
+10.43.19.1      195.113.144.238  2 u  559 1024  377    4.651    2.717   1.500
*195.113.144.201 .ATOM.           1 u   84 1024  377    1.852    1.735   1.537
+195.113.144.238 .ATOM.           1 u  127 1024  377    2.087    1.408   1.676
+147.251.48.140  195.113.144.238  2 u  148 1024  377    5.002    1.474   1.862

10.43.16.1 is my local router, which itself sync with local CZ ATOM clock source and Google NTP.

Quake logs:
kexBNet.log
kexPlayfab.log

The game is otherwise stable, tried available mods, all runs. Localnet multiplayer with bots seems to work, no crashes (three matches on normal difficulty, 10min each).

Start by reproducing Quake's online multiplayer failure with the listed Proton versions and launch options, then read steam-2310.log, kexBNet.log, and kexPlayfab.log. Compare the online lobby behavior with the working local multiplayer case; done means listed lobbies respond and players can create or join an online lobby.