May I suggest you look at this project that combines the Dexcom with your pump along with software. It is not a simple turn it on and automatically everything is perfect, however it is by far the best option right now for type 1 diabetics if you are willing to put in the effort to set it all up - which from all the testing and finger sticks indicates you are.
It has a quite nice support for different devices already, and the installation and usage is a tiny bit easier due to Android having much nicer side-loading experience compared to iOS. The project Discord has lots of tech-minded diabetics discussing...
I've been using this software for multiple years now, and it has completely changed my life to the better.
Getting algorithms like loop that are available in New Zealand AND have a bunch of evidence for being safe with toddlers is difficult.
At the moment we are using CamAPS which has been used a lot in the UK with toddlers but as far as I know Sam is the only one on it in New Zealand
https://loopkit.github.io/loopdocs/