Mom / Dad-mobiles, Kid-transporters

Might be totally not what you’re into but have you considered le petit porteur? https://www.lepetitporteur.com/en/compact-and-affordable-cargo-bike/

I want one and I’d try and build it up with some Alfine di2

I almost bought a gsd but got a Yuba spicy curry instead. I found the steering simultaneously twitchy and noodly, esp w two kids on board. dunno if it was the small wheels, very short reach or geometry. It felt like a great quality bike though.