Quoting al3xu5 / dotcommon (dotcommon@???):

> I am using Devuan (2.1) + MATE DE since 08/2016...
> Now I wish to change DE but I am in doubt: XFCE or LXDE or LXQt???

A possibly novel thought: How about starting your exploration with
'none of the above'? Based on your description of your usage of Linux,
I am puzzled by your impilicit assumption that you must use a Desktop
Environment. It sounds to me like that is simply untrue.

I'm also puzzled by your assumption that doing a comparison would
require 'too much time doing long experiments'. In my experience, that
is not the case.

Try, for starters, window managers without the DE complications. You
might like one, and thus be better off.
http://www.xwinman.org/ (always a bit out of date, but always useful)

> So what you suggest should be the first choice to bet on?

Try a few classic window managers such as OpenBox, Blackbox, FVWM,
WindowMaker, etc.

Don't 'bet on' one. Exercise your birthright of freedom to explore what
is available.