Looks like you can't have a passenger anymore either. I like to have my kid on the backseat of my e-bike.

I'm not in the market for this, but I am in the market for making my cargo bike electric. Having to slow down at a traffic light and then start from zero absolutely sucks. It goes very slow, it is rough, and you won't have time. I'd use it just for that specific use-case.

Conversion kits that add a front hub motor are relatively affordable and easy to install. Should work with most cargo bikes if you can find one that's compatible with your wheel size. Something like: https://swytchbike.com/

Front mount or trailer for kid could work, but this seems inferior to your ebike.