Can’t comment on the bergamont but I ummmd and arrrhd about wheelsize on a recent gravel build. Went with 650b initially – to make it different to the rest of my bikes [road and 29er mtb]. Was OK and in no way bad, but 2 things felt suboptimal – first they looked tiny going over uneven ground, like I was going to lose my front down every small divot. I’m guessing this is mosty psychological and I would hae got used. Second they seemed to need more pedal input on the flat to keep moving at speed. The only slight positive from my perspective was that they spin up quickly when climbing. I swapped over to a 29er wheelset and have not looked back. Clearance on the frame meant I could not increase tyre size appreciably with 650b [running 47 front and 40mm rear]. The frame is also a large size so 29er perhaps looks more in proportion.
