Another way to put this is that the only Nitrokey product that claims U2F support right now is one that doesn't do OpenPGP, and uses a lesser hardware stack.
If this does U2F, I'd be interested in knowing. I'm not saying it's impossible.
I just wanted the evidence for the assertion that this is based on Nitrokey Pro. I don't understand what U2F has to do with its advertised purpose. Obviously it's a plus if you can use it for other things, and that doesn't compromise the implementation, but there doesn't seem to be a reason it should.
If this does U2F, I'd be interested in knowing. I'm not saying it's impossible.