Cluster Backup

Hi team, when its comes to backup on clusters, Can someone advice me what would be the best practice to do? I meant do we need to do the backup on all three running CORS or just doing it in current leader would be good enough? Thank you

In the documentation, it says that you can do backups against either core nodes or read replicas:

It just depends on your workload. You don't need to target the backup specifically at the leader.

For further considerations please read that entire documentation section, it goes into a fair bit of detail about tradeoffs and how to plan for effective and safe backups.