Yes I understand and agree that this is not the right path to take.

Automation however is inevitable. There is proven tech that’s existed for decades, the only new things being added here are taxiing, takeoff and landing (and honestly takeoff and landing are already automated, they’re just not used as much)

Considering most all commercial flights are fly by wire except for taxi, takeoff, and landing… not sure

It’s unacceptable in any form.

5 tons you say?

Versioning is one way; if you have an API you can have different versions which will can change depending on version.

E.G. let’s say you have contact information coming through an API… the database can largely remain the same, but if you want to add a field or change a fields name, you could upgrade the version. When the app is ready to use the new version, switch the app over.

Rereading your question once more, I believe you can just resolve all your issues with a common API.