From the operating instructions:
"6. Press the "<" or ">" button to scroll through the source options.
Then press the "SELECT" button to confirm the selection.
The source defines the sound source of the alarm.
Possible sources: DAB, FM and buzzer. If DAB or FM is selected,
the last station played is used as the alarm."

So only "Buzzer" can be selected in addition to DAB and FM radio

I only use DAB radio

I think there's only one ringtone, but I use DAB