As described here, I've installed Pop!_OS over macOS, which works fine so far.
However, I would like to try switching back to macOS, but I can't, because the internal SSD isn't recognized by the installer:
But the installed OS boots just fine. It seems, that the SSD isn't initialized during the macOS setup. Is there anything I can do, to get the disk listed?
Okay, the solution is simple:
You have to click on View
and then enable Show all devices
. Now, the internal SSD will be displayed and you can do, whatever you want (partition, install macOS, ...).