Currently Timestream does not support CTAS statements, there is no mechanism to directly export data from Timestream to a S3 as well. As it stand now, the service has been released only recently and as time goes by it will mature with more features being added.
The simplest method would be to issue a SELECT * query using the required time-range and re-ingest back into Timestream in a new table.
I also found this 3rd party article that will help you to a certain extent  .
Following best practices will help you keep the costs down .
There is no simple method of extracting certain data from the Timestream table onto another table that I am aware of, you can also consider exporting the data to a Json file using Lambda and use Lambda to export this data to the other Timestream table but this will also require some Lambda for the same.
References:  Getting started with SDK's: https://docs.aws.amazon.com/timestream/latest/developerguide/getting-started-sdks.html
 Export table to Json: https://stackoverflow.com/questions/69943145/export-aws-timestream-table-to-json-csv
 Timestream to Json: https://www.anycodings.com/questions/export-aws-timestream-table-to-jsoncsv
if all the fixed you want to do fit in a single statement you could write a scheduled query that you manually execute once and target it to a new table
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