Hi all,
I created and published a GPT that is fully trained in the Make App Builder Documentation (About the apps builder | Make Apps). It will Make your life as a Custom App developer so much easier!
You can find it here: ChatGPT - Make Custom App Builder
Feel free to use it, if you have any problems let me know. 
Henk de Blauw
Level 5 certified Make Expert
www.operative.pro