Lucent Heart (283060) crashes upon entering world

Compatibility Report

• Name of the game with compatibility issues: Lucent Heart
• Steam AppID of the game: 283060

System Information

• GPU: RX 580
• Driver/LLVM version: Mesa 19.2.8
• Kernel version: 5.3
• Link to full system information report as Gist: (will supply if necessary)
• Proton version: 5.0-5

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.

Symptoms

The game crashes when you try to enter the game's world. Everything before (e.g. creating a character) works fine.

Unfortunately the game will hang after logging into a server if PROTON_LOG=1 %command% is added to the launch options of the game. This happens before one can try entering the game's world so I can't show logs for the specific moment where it crashes. Maybe I could try using specific Wine log options to get around this, I'll update if I manage to do so.

Reproduction

1. Download the game (free) and launch.
2. Allow the patcher to patch the game.
3. Check for updates with the patcher, this could take up to 12 hours and it can crash during the process (it picks up where it left off though, so update progress is not lost).
4. Launch the game, make an account, link to Steam account, relaunch the game
5. Enter a server (just click "Enter", the default/first one is probably fine) (don't stay on this screen for too long as otherwise it will kick you off)
6. Create a character (click "Create", bottom right, fill in character information with anything, don't hang around on this screen for too long either)
7. Click "Enter" (bottom right again)

No source file, test, or diagnostic log is identified in the report; begin by reproducing the crash after character creation and collect the missing logs if possible. Done would mean identifying the cause of the world-entry crash and confirming that Lucent Heart reaches the game world under Proton.