Perhaps the QuestDB team could add it to the Time Series Benchmarking Suite [1]? It currently supports benchmarking 9 databases including TimescaleDB and InfluxDB.
Wow! Nice. I am surprised neither Scylla nor KairosDB are on that list. I think you could run Scylla by itself (to compare with raw Cassandra) and also re-run with KairosDB running on top of Scylla and Cassandra to see what effects that has on performance. (Though of course, there are advantages to having KairosDB, too.)
[1] https://github.com/timescale/tsbs