RPGMaker MZ (1096900) [exact same problems in RPGMaker MV (363890)]

Compatibility Report

• Name of the game with compatibility issues: RPGMaker MZ
• Steam AppID of the game: 1096900

System Information

• GPU: GTX-1080
• Driver/LLVM version: 450.66
• Kernel version: 5.8.5-arch1-1
• Link to full system information report as System Info Gist here
• Proton version: 5.0-9

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.

RPGMaker MZ Gist here

Symptoms

• "Help -> Contents" freezes the game
• Tiny white box artifact when using the tutorial
• In the first tutorial when typing in text, you have to click the text box multiple times for it to register that you are selecting the text box (have to fight it to type)
• In the first tutorial when you open the "database", the program slows down for a few seconds (regardless of hardware) and has ghosting of the cursor/tutorial window (think of old-school solitaire ghosting on Windows). It does fix itself after those few seconds.
• When doing the first tutorial, the "stone cave" icon disappears when you go to the next step. Not sure why.
• Playtest screen pops up for a second and then disappears (supposed to load your game)

Reproduction

Below is my current system, but I also tested it on an Ubuntu 20.04 system with the same results

OS: EndeavourOS Linux x86_64
Kernel: 5.8.5-arch1-1
Shell: bash 5.0.18
Resolution: 2560x1440
DE: Xfce
WM: Xfwm4
CPU: AMD Ryzen 7 2700 (16) @ 3.966GHz
GPU: NVIDIA GeForce GTX 1080
Memory: 2772MiB / 32125MiB

Start by reviewing the RPGMaker MZ and system-information gists, then reproduce the listed symptoms with Proton 5.0-9 on the reported Linux systems. Compare the Help freeze, tutorial artifacts and input behavior with the RPGMaker MV report; done requires isolating and documenting a reproducible compatibility cause and fix.