'Engineered oak' has become a catch-all term, but the floors it describes vary enormously. The difference is in the layers you cannot see.
Many engineered boards are a thin timber veneer over plywood. HARO builds around a solid spruce core with a substantial 3.5mm oak wear layer, made in Germany to a single standard and backed by a 30-year warranty. It is a floor built to last generations, not seasons.