From our tests we have a few benchmarks and your result isn’t too far off what we would expect. But, results can vary depending on the size of the rows, the number of machines in your cluster and the distribution of ranges in the cluster.
Could you clarify what 100m CPU means? The Kubernetes documentation leads me to believe that 100m of CPU means .1 cpu, which would mean that your machine is under provisioned for running CRDB.
You could most likely verify this by on the hardware tab of the admin UI when running your query.