The Dragonfly benchmark which showed 25x faster was run on c6gn.16xlarge which has 64 vCPU. The m5.4xlarge you used "only" has 16 vCPU. Since Dragonfly is achieving its performance by using multiple threads it's not weird that you weren't able to replicate its performance gain.
In my opinion, when it comes to these types of multi-threaded benchmarks it's much better to separate the "baseline, one-process performance" from "how it scales with number of processes". E.g. if you first pin Dragonfly to only run on a single core you can find the baseline performance compared to Redis, and then you can run different benchmarks of Dragonfly with increasing number of cores to see how it scales. This should give you much better understanding of how the system behaves. (The release of Dragonfly actually prompted me to write a blog post on this: https://t.holmium.no/dia/apples-vs-oranges/)