proton_roblox.sh

#!/bin/bash
# Adapted from https://www.toptensoftware.com/blog/running-ea-origin-games-under-linux-via-steam-and-proton/

# Add custom windows exe to steam (usually it's an installer)
# this creates a directory with a big number as an id, look for it
# in .steam/steam/steamapps/compatdata
COMPATDIR=3999685975

# Pick a Proton Version  (steam/steamapps/Proton... for official steam protons)
PROTONVER=root/compatibilitytools.d/Proton-6.1-GE-2

# In this case I'm setting up roblox, 
#go to the wine prefix of the compatdata directory and find the executable I want to run
ROBLOX_EXE="pfx/drive_c/Program Files (x86)/Roblox/Versions/version-d582aaa830b4437a/RobloxStudioBeta.exe"

# Steam prefix directory
export STEAM_COMPAT_DATA_PATH=~/.steam/steam/steamapps/compatdata/$COMPATDIR/

# Run
PROTON_LOG=1 ~/.steam/"${PROTONVER}"/proton waitforexitandrun \
    "${STEAM_COMPAT_DATA_PATH}${ROBLOX_EXE}"