Both LXDE and LXQt is build around Openbox Window Manager
LXDE has been based on GTK2 and most - if not all - LXDE specific components has been ported to GTK3.
The Manjaro LXDE Community edition is using the GTK3 versions - so not dead.
And the LXDE edition has just been released as v20.2.1.
And what ever you are referring to - most of those posts are from 7 years ago - and LXDE is not dead - not at all.
Qt is not my favorite either - but it has improved over the years - and with some decent theming - LXQt is quite usable.
This comment from lxde forum - says it better than I
If people understood better what LXDE really is, they wouldn’t be so worried about it dying.
what defines a desktop ebvironment?
a) session management
b) applications that somehow fit together
a) LXDE’s session management is very rudimentary (i know it got a little more complex in recent years but still next to nothing compared to the likes of GNOME)
b) the applications it consists of: only very few are specific to LXDE: lxappearance, pcmanfm, lxrandr, lxsession, lxpolkit
even so they work well without the whole DE and enjoy some popularity outside of LXDE.
many applications are not even original LXDE apps: openbox, Firefox or whatever browser is installed.
the applications are sufficiently maintained and apart from the browser (which isn’t part of LXDE anyhow) there isn’t any security risk.
so, relax everybody.
also, it’s still many years (at least a decade is my guess) until Xorg will not be a mainstream option anymore and everybody is using wayland.
If LXDE is deprecated, can it still be used safely? - LXDE Forums