Running Windows games via Proton without going through Steam or Lutris
From Pengwings
This example runs Warcraft III: The Frozen Throne
Specific Proton versions can be downloaded and added to the Steam compatibility tools directory using ProtonPlus from https://protonplus.vysp3r.com/ installable from Flathub
How to do it
Create proton prefix directory
mkdir /opt/games/_pfx/wc3
Put this run.sh script in the installation directory of the game, setting configurable settings as needed. If you need to set extra environment variables then you can do that here
#!/bin/bash -x
#---------- CONFIGURABLE SETTINGS ----------
export STEAM_COMPAT_DATA_PATH="/opt/games/_pfx/wc3"
TARGET_PROTON_VERSION=GE-Proton10-29
PROGRAM_NAME="Frozen Throne.exe"
PROGRAM_ARGS=-window
#---------- THE SCRIPT ----------
export STEAM_COMPAT_CLIENT_INSTALL_PATH=~/.steam/steam
SCRIPT_DIR=$( cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )
pushd "$SCRIPT_DIR"
$STEAM_COMPAT_CLIENT_INSTALL_PATH/compatibilitytools.d/$TARGET_PROTON_VERSION/proton run "$SCRIPT_DIR/$PROGRAM_NAME" "$PROGRAM_ARGS" & disown
popd
Mark the script executable, open Terminal and try to run it, it should work
If it works you can create a .desktop file for it and add it to the KDE Application Launcher