The API documentations says
Don’t use this API to create new apps; instead, create new apps on the App Store Connect website.
https://developer.apple.com/documentation/appstoreconnectapi/app_store/apps
If I am going to the App Store Connect API documentation, it's not because I want to create things from a UI.
Is there any valid reason for not having an endpoint for that?
Thanks
I think the aim of the API is to let you automate bulk updates that would be tedious to do manually. For example, changing the prices of 1000 in app purchases.
Apple don't want developers to have hundreds of (similar) apps. They would prefer you to have a single app with IAPs for all of the different variations.
So they don't want to make it too easy to create lots of apps quickly, and it's therefore not in the API.
Just my theory...