The managed cloud feature is great, so if there's a comparison happening it'll be much more valid if you do a like-to-like one. I'd be more interested to see that the numbers (performance and cost would be) if you ran the comparison with Timescale Cloud managed, on AWS, with EBS set up (and note IOPS settings) at a comparable provisioned size with multi-AZ failover. Doing that and checking costs would be much fairer from a cost-per-metric point of view.
We report numbers in the blog post with our managed offering Timescale Forge, running on AWS with storage replicated across AZs and supporting automated failover.
Not sure about "comparably provisioned re: IOPS" given that you don't know about that at all with AWS Timestream, but our blog post reports the performance/cost of a suitably provisioned Timescale Forge instance (8vCPU / 1TB storage).
100GB ingest then query benchmarks took far less than 1 hour with Timescale Forge @ $2.18/hour.
The "consumption based pricing" for AWS Timestream for same benchmark took $336.40.
