What do we have here. LXQT + IceWM ( Trisquel Theme ) + Picom. At the moment I am only with Qt applications I don't expect a very well integration with GTK3 apps, I will see.
After some research for alternatives the only one that I found quite close to Dolphin is Pcmanfm-qt. If each of the software is visually correct ( even if I had to fix icons issue on PcManfm-qt ) it is quite different when it comes to use and configure Pcmanfm-qt which is still being very far from Dolphin. ( Also note the issue in the arrangement of the folders in pcmanfm-qt ). A little bug however with Dolphin where 'minimize' and 'Maximize' are not available.
PCMANFM-QT
DOLPHIN
I am far from being convinced by pcmanfm-qt and for now Dolphin wins the match.
Others remark like the connection via the network to an ftp server, which does not work on pcmanfm-qt and the inability to change the size of the icons on the fly.
Still a lot of work to be done on Pcmanfm-qt and at the speed at which development is going on we should reach a similar level in twenty years :D
Others files manager I have tested.
QTFM
INDEX-FM
I have to admit that has nothing to do with the
beautiful screenshots from their website...
Anyway, in any case Dolphin wins the match.