[Lazare]

I would say that all software engineering jobs are about integrating existing projects, although ideally that would be accomplished by building something interesting.

Often we draw some artificial line and ignore everything below that. If you draw the line right below where you're working, then you can "I'm building a system from scratch! Just using [Excel|a web browser|AWS services|NPM libraries|C standard lib|an assembler]."

I'm not sure there's any obviously "right" place to draw the line. The people working on better compilers are building on a stack of technology so vast they can't see the bottom, even if they're clearly many, many levels below where I am tinkering with some payment code talking to Stripe's APIs.