I am guessing the Pi 4 is going to stay the same? Than simply switching out the Raspbee for a Conbee should work. Be sure to make a backup first either through the Phoscon app or by making a copy of the zll.db file.
Than making a backup and restoring it on the new installation should work. In my case I had to copy the zll.db file directly which can be found in ~/.local/share/dresden-elektronik/deCONZ.
Is it possible to gather the data mentioned in the screenshot above from a headless installation (gui, xserver etc. not available) and to set it to a headless installation? Stay the data in some kind of config files or similar?