File picker problems in KDE (xorg)

Playing around with appimages from apprepo in Manjaro (Arch-based KDE distro).
Downloaded far2l and chrome, created .config and .home folders in the directory of each appimages. They definetely use their own folders for config storage, not user home.
When I launch Chrome.AppImage directly from Dolphin (KDE filemanager) or via .desktop file - the file picker doesn’t work (i.e. Ctrl-O does nothing, and any website where you upload files from disk do not open the file manager). Dragging files work though. In XFCE-Ubuntu, the file picker opens a file selector dialog.
When I select and press enter on any registered file type, i.e. jpg in Far2l, nothing happens. In XFCE-Ubuntu/Debian, in the same scenario the file is opened in corresponding application as per xdg-open (i.e. in this case the jpg will open in associated picture viewer).

However, when I select and press enter on the same Chrome appimage in Far2l (i.e. using Far as file manager, not Dolphin), the file picker in Chrome works! It’s the same appimage, on the same OS install.

Where to even start looking for possible reason for such behavior and fix?
I suppose the Far2l appimage has some dependencies bundled, which are required by Chrome appimage to work, and that are not installed in the OS itself. So when chrome is launched thorugh far2l, it just has uses the libs in the /tmp. How to find which ones?

Hello @izzylaif. This seems to be a question about the applications themselves, not about the AppImage which they reside in.
So please ask the developers of the respective applications; we don’t know how they work. Thanks!