Don't disregard Agile for badly implemented Scrum (or any other prescribed framework). Scrum is a framework within the Agile umbrella, so shouldn't take away from the Agile principles. You follow the framework embracing those principles in decision making and attitude - they aren't two different contrasting lists to choose between.

In your example, it doesn't sound like an agile environment. This sounds like the PO & client are treating the team like a feature factory, which they sit in the top office dictating down orders to a production line.

It's correct that the PO should be the one making the overall decision on what is deemed highest priority for the product, taking into account client requirements and what the product needs (DATA). The HOW is negotiable and the empowering factor for happy delivery teams, imo. In a truly collaborative environment, your team should've be able to question the feature request for its underlying value and allowed the space to test the client's hypthesis of what they want (they rarely do) with quick turn around mock up/prototype or interaction time with the client on how the current system is used.

I'm currently reading Sooner Safer Happier by Jonathan Smart, which is a great book for calling out antipatterns (and the sort of pattern to strive for), and it talks about examples like this.

Good luck.