KDE plasma. From my experience it uses less resources than lxqt and xfce and works out of the box while lxqt and xfce required extra work to get wifi, screen brightness controls and audio working. I can have 10+ tabs in a chromium based browser open without lag on an old laptop with 2GB ram and 1.33 - 1.83GHz 4 core intel atom from 10 years ago.