Does separate Authentication is required for the each geo-locations(Tenant Instances) ? if Authentication done then will there be any changes in the CSOM Data ?
Separate authentication is not required for each geo-location, but there may be variations in data availability or latency based on the specific services and regions involved. The CSOM data you access will reflect the data available in your Microsoft 365 tenant, which can span multiple geo-locations depending on the deployment and configuration of your tenant.