By the way, I use Plasma on my everyday job and I can't complain of it.
It's fast, feature full and works very well. (I never seem to understand how people complain of it being slow, bloated, whatever... Mine isn't!!) The thing I love the most in it is being able to set it in whatever way I want. I never get tired of it and so far it hasn't let me down. I'm always amazed that, whatever crazy idea I think of that can speed up my work, or make me more comfortable about my DE, they have an option for it!!!
It's a kind of freedom I can't find anywhere else.
For older computers where every MB counts (plasma uses around 350-500mb), or for people who don't care about extreme customizations (that are happy with an XP/7 like DE), then LXQt is used
Also time matters for me because I am mostly using my keyboard, chaining commands, so I start imputing stuff right after I open it and if those commands are missed because the application is still loading it sucks.
Fair enough!!!
Have you tried PCmanFM and LXQt? I think you'll be pleased
I'll do another set of tests once Ubuntu (or rather PopOS) 20.04 LTS releases.
It's very lite (you won't notice the difference when compared to openbox) and it's feature full/very powerful.
LXQt devs have mentioned they will probably migrate to kwin when Wayland arrives for good.
(and forget lxde. LXQt is the future ;)