Engineering-first culture is almost always the wrong idea. It's product-first or nothing. The entire point of agile is prioritization based on business value. Everything always takes longer than estimated regardless of how you manage your project. That's actually a core tenet of agile and one that stakeholders (and budget holders) have the hardest time accepting. Having worked in this industry before agile was prevalent, I can assure you it was never better than this in the past. QA as first-class is a pretty core principle as well. The point of things like Scrum is meant to be visibility and alignment rather than prediction, but impatient people are guaranteed to ruin your life no matter what.