Earlier quoted context omitted.
I used DynamoDB as part of the job a few years ago and never got single-millisecond responses - it was 20ms minimum and 70+ on a cold-start, but I can accept that optimising Dynamo's various indexes is a largely opaque process. We had to add on hacks like setting the request timeout to 5ms and keeping the cluster warm by submitting a no-op query every 500ms to keep it even remotely stable. We couldn't even use DAX be…
No need to guess when you can measure. I am running https://cloud-canary.com a service where I monitor AWS primary services for latency and availability. It comes with a lot of data. For instance this is the latency I see doing operations against Dynamo. https://cloudcanary.grafana.net/public-dashboards/c53e2092d6...
Little bit of well meaning advice: This needs copy editing -- inconsistent use of periods, typos, grammar. Little crap that doesn't matter in the big picture, but will block some from opening their wallets. :) ("OpenTeletry", "performances", etc.)
All in all this is quite cool, and I hope you get some customers and gather more data! (a 4k object size in S3 doesn't make sense to measure, but 1MB might be interesting. Also, check out HDRHistogram, it might be relevant to your interests)