I think you may mean Ghost Commander, I use it on Android and it fits your description.
When I’m on Windows and need two panes, I open two Windows Explorer windows.
Two explorer windows are independent of each other. Any move or copy requires two keyboard actions or the use of the mouse
The orthodox file manager was created for copying files between two disks. File management on my phone still follows the same pattern: copy or move something between the phone's storage and, for example, an SFTP remote. The remote directories are pretty stable; it makes sense to bookmark them.
Meanwhile, on my computer one-off mass copying has become rare compared to the era of removable media. Most of my mass file operations are moving files to or from a subdirectory in a code project or renaming them. This is an awkward fit for an OFM: you need to go to directory A, duplicate its path to the other pane, switch to the other pane, and then navigate up or down a level to directory B. A dynamic "parent directory" or "../foo/" second pane might help.
Nowadays I mostly use clones like Midnight Commander, Krusader and Double Commander, and I used Worker (a clone of a clone, this time a clone of Directory Opus for the Amiga) for a long time before settling on Krusader as main one. The genealogy of these file managers is kind of fascinating.
Anyone else a fan?