Send-it sends file(s) via Bluetooth to a selectable connected device, such as mobile phones.

requirement:
KDE command line tool: bluedevil-sendfile

the file contains an example to create additional private menu items for sending to specific devices (which skips the device selection dialog)
to create these, you have to edit it in ~/.local/share/kio/servicemenus/send-it-bluetooth.desktop or ~/.local/share/kservices5/ServiceMenus/send-it-bluetooth.desktop

Note:
Although the command line option '--files' imply that bluedevil-sendfile can handle *multiple* files at once (and send-it is modeled after this by using %U instead of %u), this seems to be a false assumption. only the first file on command line is send.

Note OBEX:
At least Fedore throws an error on not activatable service org.bluez.obex, which maybe a packaging error (as bluedevil lists 'bluez-obexd' as a requirement), but this fixes it:
$ sudo dnf install 'bluez-obexd'