Look for the phrase "scale-up" instead of "start-up", these are usually well-funded, up-and-running companies that still have some of the start-up mentality but without the financial worries.
Of course, some of these are already a decade old and may employ hundreds or thousands of people already, so YMMV; they might just be like older, boring enterprises, just not as formal or fixed in their ways.
Those are companies that believe they have product market fit though. At that point they are starting to transform from a startup into an established company.
So most of the early stage learnings can no longer happen.
Of course, some of these are already a decade old and may employ hundreds or thousands of people already, so YMMV; they might just be like older, boring enterprises, just not as formal or fixed in their ways.