I have managed to work around the launcher with the following setup:
Create a run.sh script in your steamapps/common/Kerbal Space Program 2 with the following content:
#!/bin/bash
ARGS=()
for i in "$@"; do
ARGS+=("${i//PDLauncher\/LauncherPatcher.exe/KSP2_x64.exe}")
done
exec "${ARGS[@]}"
Make it executable and change the steam launch options to "/path/to/your/steam/lib/steamapps/common/Kerbal Space Program 2/run.sh" %command%
The script can, theoretically, be put anywhere as long as it is executable and the steam launch options are adjusted accordingly.