https://blog.afandian.com/2019/09/ux-for-toddlers/
Thanks for the video, I love seeing performances like that.
I've been fascinated with those grid MIDI controllers for a while. I started this project with a Launchpad Mini but didn't have the energy to work out how to make it battery powered and reliable (there's an excellent Python library but it was a bit flaky with a Raspberry Pi).
I wonder how you use them in reality. Learn a new layout for every song? I can play a few instruments' keyboard layouts, but it would be a challenge to remember where each sample was mapped.
There is usually no predefined layout (exceptions apply), but more modern controllers with certain software allow you to save your presets and transfer between different projects (kinda like a template).
Normally, it is like a giant chessboard, and you map synths/samples/etc. individually for every new project. So if you are used to having all drums in the top right corner, you can just assign them there on this controller.