Thanks for the input.

To make an informed choice, I'll ask a dealer about replacing the 8-speed Shimano Nexus Premium IGH with an Alfine 11 on a 2015 City.

Provided it's possible, the choice would then be between a second-hand 2013 Birdy Touring with the 24-speed Dual Drive and Magura hydraulic rim brakes (1.76 - 8.89 m), or a 2015 City with an Alfine 11 IGH and Shimano hydraulic disk brakes (2.3 - 9.9m).