I used XFCE from 2006 until around 2011 and it was pretty nice and lightweight. Then I switched to a laptop running Gnome for a few years, but noticed later versions became a bit sluggish. On my current machine (a laptop based on Ryzen 7 with 40 GB of RAM) I switched to KDE Plasma because its performance is pretty good, it's compatible with Wayland and it has a lot of built-in applets and stuff. And it didn't have the frequent CPU activity spikes I was seeing with Gnome.

Despite the lack of Wayland support, XFCE is really nice, although I'd consider LXDE or Enlightenment on a low RAM machine. Enlightenment looked amazing last time I tried it on an old laptop.