What is a viable low-cost DR option for a large cluster?

We have a Cassandra cluster running on GKE with a 32-CPU node pool and SSD disks. The current cluster size is nearly 1 PB, with each node utilizing an average of 5 TB on 10 TB allocated SSD disks. The cluster comprises 200 nodes, each with 10 TB disks, totaling 2 PB in size total allocated. Given this cluster size, the maintenance costs are substantial. How can we achieve low-cost disaster recovery for such a large cluster? One option I am considering is creating a new data center in a different region with a replication factor of 1 (RF1). While this is not recommended, it would at least reduce the cluster size by a factor of three. Any suggestions would be greatly appreciated.