I will also jump in to say that KDE is very close to XFCE in resource usage, especially with Manjaro. It’s very light and snappy - one of the fastest and smoothest I’ve used.
This is on my laptop:
When I tested XFCE in Virtualbox, it was around the same.
Is that Solus Budige, Ubuntu Budgie, or other? Budgie and Pop!_OS are the lightest GNOME mods I’ve used (aside from a completely minimal manual GNOME install). Both use forks of GNOME Shell (Cinnamon, from the folks at Mint, in the case of Budgie) with other extraneous GNOME bits slimmed down, so fast is to be expected.
Was Budgie on Manjaro. I figured it out by now. Where two packages that where missing. gvfs-* something. I can look it up is someone is interested.
Looks like this will be what I put on my highschool ebook