Riese and Muller bikes are built to invade Poland, no bad thing for an ebike.
I've not ridden a Nevo, but I bet the girder frame cures the problem of flex with a low-step.
Declaring an interest, I have the previous model Charger, bought mostly because I wanted twin batteries and a Rohloff hub.
Which brings us to another benefit, you get decent quality branded components with a Riese and Muller bike.
To name a few, Thudbuster seatpost, XT gears, Supernova light, Magura four pot brakes - worth having because an ebike takes some stopping - Alex rims, Novatec hubs, and SKS mudguards.
Mine came with a Suntour Aion fork, which is air and has magnesium legs.
As my local bike shop commented, you are probably better off with a higher model Suntour than a cheap Rockshox.
The Aion is fully serviceable, although I'm not too keen on Suntour's too clever for its own good QLoc through axle.
Another plus is the ability to spec quite a few options, include Bosch displays, battery size and dual battery.
The carrier on the Nevo is Riese and Muller's own design, but I can guarantee it will be at least as strong and durable as a Tubus.
All of which comes at a cost in terms of money and weight, but the OP's bike shop is correct in saying Riese and Muller are about as premium as you will get in ebike terms.
Yes, you could put a £750 Chinese kit on a bike Skippy would approve of, but not everyone wants to do that.
https://www.r-m.de/en-gb/bikes/nevo3/