(Unfortunately, not all Android One devices are recorded as such here, I've noticed that too. As an Android One fan, this also bothers me a lot. :-( Android One is listed as "Android version" (along with ... 8, 9, 10 etc.), which is of course not true and makes things doubly difficult. I always inform myself beforehand here: https://www.android.com/one/)
Yes, the device has an FM radio, but you need cable headphones for it, because the cables serve as antennas for reception. Here is how to do it: https://www.nokia.com/phones/en_ie/support/nokia-8-3-5g-user-guide/fm-radio
Galaxus Germany is, as far as I know, a separate company and they also have other suppliers.
The 8.3 is available with headphones for 499.- on Digitec.
Nokia 8.3 incl. Power Earbuds BH-605 (128GB, Polar Night, 6.81", Hybrid Dual SIM, 64Mpx, 5G)
Operationally, Digitec is independent of Migros, and also has other suppliers, unlike Melectronics. Most sources give September as the start of sales, so it is doubtful that Melectronics can really deliver in 8 days.