Software quality is not related to test cases, automation and shift left something.
It is about your (and your engineers) knowledge and skills.
Read books/articles about software engineering - it will help you a lot.
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en.m.wikipedia.org/wiki/Co…ramming)
An image shows modules coupling in real project.
I guess, 65% of senior developers and 90% of QAs around the world don't even know what that is.