Hi David,
You could use something like
date_bin('2 weeks'::INTERVAL, roundts,'2023-01-01T00:00:00Z'::TIMESTAMP)
but if you are going to partitions over smaller periods of time please keep in mind the total number of shards in the cluster and the size of those against the recommendations in Sharding and Partitioning Guide for Time Series Data - Tutorials - CrateDB Community
I hope this helps.