I’m not sure where you’re from, but in Spain and Germany, I still found available devices in third party sellers. While in the official Nothing webpage the phone might appear as sold out, I’m pretty sure you can still get a device in a third party electronics store, or maybe even on amazon (today and tomorrow are prime days with discounts).
So make sure to check some other trustable sellers.
PS: I bought my Phone (2) in February for 520€, so you can have an idea on which price range to expect