This article provides information on renaming a vSAN Datastore even if VMs are running on it.
VMware vSAN
vSAN datastore can be renamed while there are production virtual machines running. The renaming of the vSAN datastore won't change the UUID of the datastore, only the name itself.
To rename the vSAN datastore, please follow below.
The system enforces an 80 character limit for the datastore name.