Anno 1800 multiplayer not working anymore

[Asteliks]

Compatibility Report

• Name of the game with compatibility issues: Anno 1800
• Steam AppID of the game: 916440

System Information

• GPU: Nvidia RTX3080
• Driver/LLVM version: nvidia 525.89.02
• Kernel version: 6.1.14-200.fc37.x86_64
• Link to full system information report as Gist
• Proton version: Proton Experimental (as of 2023/02/27) & 7.0-6

I confirm:

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

steam-916440-.zip
proton-6.3-8 crashes so fast that no log is created

Symptoms

Unable to join multilayer games with the latest proton version. According to comments on protondb it used to work with proton 6.3-8 but unfortunately I'm getting an error when trying to start with that proton version.

Reproduction

1. Start Anno 1800 with Proton 7.0-6
2. Host a multiplayer game see that no one can join you. Be that through the game, steam or Ubisoft connect;
3. Try joining your friends game (Friend was on Windows 10). See that the game tries to join you but fails with no error message;
4. Try running Anno 1800 with Proton 6.3-8 as recommended on protondb;
5. See that ubisoft connect crashes on lunch;
6. Check game files -> same result with ubisoft connect;
7. Reinstall the game;
8. Lunch running Anno 1800 with Proton 6.3-8;
9. See that ubisoft connect crashes on lunch.

[kisak-valve]

Hello @Asteliks, we're using one issue report per unofficially supported game title, so I've gone ahead and transferred this issue report to #2544 (comment).