SteamAlt is a simple GUI tool that allows you to copy game data (saves, settings, etc.) between different Steam accounts on the same computer.
https://ritze03.github.io/SteamAlt/
sudo echo
wget https://github.com/Ritze03/SteamAlt/releases/download/release/SteamAlt-Linux -O ~/Downloads/SteamAlt-Linux
sudo cp ~/Downloads/SteamAlt-Linux /usr/bin/steamalt
sudo chmod +x /usr/bin/steamalt
steamalt