If we use a house building/construction analogy, in this comment chain we're saying software engineering is inclusive of house design/architecture down to wall construction, plumbing, electrical, etc. Following that analogy then I think when Xeoncross is asking about "hardcore engineering" that really would equate to new engineering products for the house building industry - like some new tech like solar roofing shingles (instead of raised solar panels).
There aren't a lot of companies that are doing that in software. For example, there are a lot of SaaS businesses doing things that might have interesting engineering problems to solve but those engineering problems usually don't result in creating new products for software engineers to use. Rails is a good example of a byproduct from a SaaS business, React is a byproduct of whatever Meta does.
I actually don't know for certain that writing Rollercoaster Tycoon in assembly was the not only possible way of doing it. But in popular consciousness it is usually discussed as a wildly difficult thing rather than the most efficient solution to a problem. That's anti-engineering.
There isn't really a good set of words to break down categorization. But I do think that the skills involved in the large majority of software engineering roles are pretty much entirely separate from the skills involved in writing some exceptionally difficult program.