The functions of research papers and review papers are quiet different (see, e.g. https://www.editage.com/insights/what-is-the-difference-between-a-research-paper-and-a-review-paper). Review papers are very useful as overviews of a field of science, especially when there is an overwhelming amount of publications or when you are new to this field.
As far as I am concerned, a lot of work has to be replicated. A single paper or study (with often a small sample) is not conclusive enough. Hence, there is benefit from replication - and reviews, more broadly.
To answer your second question - about hunting for ideas and going for it, I agree that is what I do as well. I am now (thankfully) more experienced and can develop the methodology better for addressing the question(s) at hand.
Originality in science is important, and continuity in scientific results is also needed, so that results replicated from existing research do not contribute any of these, not originality or scientific continuity.
Every idea we express should be as original as possible. Of course, when we read about different topics, in some cases these topics stay in our minds and give rise to similar works. But if we want to move forward it is necessary to put into practice new ideas, new research topics or focus on little studied topics and thus we will achieve a greater contribution to the field of study.