Helping script that automatically installs the Media Foundation workaround for Wine (https://github.com/z0z0z/mf-install) to the latest Proton Version

mf_install_helper.sh

#!/usr/bin/env bash

# If the following variables are not empty there will be no command line dialog
# for them
CUSTOM_STEAM_ID="" # "922500"
CUSTOM_STEAM_NAME="Custom" # "KIllLaKIllIF"
CUSTOM_PROTON_VERSION="" # "- Experimental"
CUSTOM_STEAM_GAME_DATA_LOCATION=""
ASK_FOR_CONFIRMATION="" # Anything other than empty string disables confirmation

# Stop script if a step fails
set -e

STEAM_APPS_DIRECTORY="$HOME/.local/share/Steam/steamapps"
STEAM_APPS_DIRECTORY_COMMON="$STEAM_APPS_DIRECTORY/common"
if ! [ -d "$STEAM_APPS_DIRECTORY" ]; then
	echo "Error: Steam apps directory location '$STEAM_APPS_DIRECTORY' was not found. Can not continue."
	exit 1
fi
if ! [ -d "$STEAM_APPS_DIRECTORY_COMMON" ]; then
	echo "Error: Steam apps directory common location '$STEAM_APPS_DIRECTORY_COMMON' was not found. Can not continue."
	exit 1
fi

# Select which game should be updated if not already selected
STEAM_ID=-1
STEAM_NAME="None"
if [ -z "$CUSTOM_STEAM_ID" ]
then
	PS3='Enter/select your Steam game id: (if not listed enter Steam ID) '
	options=("Gris" "PummelParty")
	select opt in "${options[@]}"
	do
		case $opt in
			"Gris") STEAM_ID=683320; STEAM_NAME="Gris"; break ;;
			"PummelParty") STEAM_ID=880940; STEAM_NAME="PummelParty" break ;;
			*) STEAM_ID=$REPLY; STEAM_NAME="Custom" break ;;
		esac
	done
else
	echo "> \$CUSTOM_STEAM_ID ($CUSTOM_STEAM_ID, $CUSTOM_STEAM_NAME) was found"
	STEAM_ID=$CUSTOM_STEAM_ID; STEAM_NAME="$CUSTOM_STEAM_NAME";
fi

# Select the path where the game data is located
GAME_DATA_LOCATION="$STEAM_APPS_DIRECTORY/compatdata/$STEAM_ID"
if [ -z "$CUSTOM_STEAM_GAME_DATA_LOCATION" ]
then
	PS3='Enter/select where your Steam game is located: (if not listed enter Steam game location) '
	options=("(default) '$STEAM_APPS_DIRECTORY/compatdata/$STEAM_ID'")
	select opt in "${options[@]}"
	do
		case $opt in
			"${options[0]}") break ;;
			*) GAME_DATA_LOCATION=$REPLY; break ;;
		esac
	done
else
	echo "> \$CUSTOM_STEAM_GAME_DATA_LOCATION ('$CUSTOM_STEAM_GAME_DATA_LOCATION') was found"
	GAME_DATA_LOCATION=$CUSTOM_STEAM_GAME_DATA_LOCATION
fi
if ! [ -d "$GAME_DATA_LOCATION" ]; then
	echo "Error: Steam game data location '$GAME_DATA_LOCATION' was not found. Can not continue."
	exit 1
fi

# Ask for specific proton version
PROTON=""
if [ -z "$CUSTOM_PROTON_VERSION" ]
then
	proton_versions=($( find "$STEAM_APPS_DIRECTORY_COMMON" -maxdepth 1 -regex ".*Proton.**" -type d -printf '%f\n' ))
	proton_versions=(${proton_versions[@]//Proton*/})
	echo "Select the correct Proton version: "
	select proton_version in "${proton_versions[@]}"
	do
		proton_version_index=$REPLY
		proton_version_index=$((proton_version_index - 1))
		PROTON="$STEAM_APPS_DIRECTORY_COMMON/Proton ${proton_versions[$proton_version_index]}"
		break
	done
else
	PROTON="$STEAM_APPS_DIRECTORY_COMMON/Proton ${CUSTOM_PROTON_VERSION}"
fi
if ! [ -d "$PROTON" ]; then
	echo "Error: Proton directory '$PROTON' was not found. Can not continue."
	exit 1
fi

# -----------------------------------------------------------------------
# The important part [Variables] (begin)
# -----------------------------------------------------------------------

export WINEPREFIX="$GAME_DATA_LOCATION/pfx"
export PROTON="$PROTON"

echo "MAKE SURE THAT ALL PATHS ARE ABSOLUTE AND NOT RELATIVE!"
echo "STEAM_ID:   '$STEAM_ID' ($STEAM_NAME)"
echo "WINEPREFIX: '$WINEPREFIX' (exists)"
echo "PROTON:     '$PROTON' (exists)"

# -----------------------------------------------------------------------
# The important part [Variables] (end)
# -----------------------------------------------------------------------

# Ask if the critical execution should be started
if [ -z "$ASK_FOR_CONFIRMATION" ]
then
	echo "Are you sure to continue with the selected values?"
	select yn in "Yes" "No"
	do
		case $yn in
			"Yes" ) break;;
			"No" ) exit 0;;
			*) exit 0;;
		esac
	done
fi

# -----------------------------------------------------------------------
# The important part [mf-install] (begin)
# -----------------------------------------------------------------------

rm -rf mf-install
git clone --depth=1 https://github.com/z0z0z/mf-install.git
cd mf-install

./mf-install.sh -proton

cd ..

# -----------------------------------------------------------------------
# The important part [mf-install] (end)
# -----------------------------------------------------------------------

WINEPREFIX may be incorrect if you install your games on a different hard drive from the drive where Steam is installed. Proton will be installed on the same drive as Steam, e.g. /home/syncrossus/.local/share/Steam/steamapps/common/Proton 4.11 in my case, whereas GRIS's compatdata is on your games drive, e.g. /run/media/syncrossus/GAMEDRIVE/Software/steamapps/compatdata/683320/pfx in my case.

@Syncrossus Thanks for the feedback - the script should now be able to deal with that by letting you specify the game data location (either with a variable in the script at the top [CUSTOM_STEAM_GAME_DATA_LOCATION="/run/media/syncrossus/GAMEDRIVE/Software/steamapps/compatdata/683320"] or using the command line input during the execution).
I also added the option to select a specific installed Proton version if this would ever be a problem.
I hope it still works :D