The Settlers Online

Create .local/share/application/TSO.desktop inside your home directory with this content:
[Desktop Entry]
Name=TSO
Comment=Play this game on Lutris
Exec=lutris lutris:rungame/the-settlers-online
#Icon=
Terminal=false
Type=Application
Categories=Game
MimeType=x-scheme-handler/tso;x-scheme-handler/tso;

then execute:
$xdg-settings set default-url-scheme-handler tso TSO.desktop

You must not open the game directly from Lutris, instead you should open your browser and point to the following URL:
https://www.thesettlersonline.com
then login with your user account and choose the right handler for tso protocol.

N.B. on Firefox you must open about:config page and set widget.use-xdg-desktop-portal to true in order to manage xdg handler correctly.

Change the default installation path to:
"C:/Program Files/Ubisoft/The Settlers Online/"