I have not personally used this, but the write-up seems solid to minimize
downtime to help you to shift data gradually. Be sure you understand the
limitations of partitioning, particularly when you are still on 10x not yet
on v11 where updates will shift a row to a new partition if the partition
key is updated.
https://www.depesz.com/2019/03/19/migrating-simple-table-to-partitioned-how/