Meaning, the screen is always split in two. On both sides, there's a directory shown. All commands (copy, move, etc.) now instantly have a target (namely, the other side).

Ah, right, that seems on now you point it out.

I use Q-Dir at work because I’m constantly managing files on four networked devices.

No affiliation, just a satisfied user.

http://www.softwareok.com/?seite=Freeware/Q-Dir/Screenshots

I used Solid Explorer when I was on Android and that's exactly how it was set up. I really can't think of a better design pattern for a file manager on a mobile device.