Microsoft 365 for enterprise workloads - I Love Montreal

Best practice
We highly recommend that you deploy and roll out the Identity phase of the foundation infrastructure prior to onboarding your users to any workloads or scenarios.

The Identity phase ensures that your cloud-based identity, whether cloud-only or synchronized with your on-premises Active Directory Domain Services (AD DS), contains the user and computer accounts and groups to manage authentication and access. Strong authentication for all your users along with strong protection of admin accounts is required before placing your organization's digital assets in the Microsoft 365 cloud.

Although foundational and very important to overall performance, the rollout of the Networking phase can be in progress while onboarding your users to workloads, with the understanding that Microsoft 365 workload and service performance will improve over time. This is especially true for enterprise organizations with multiple locations and a mixture of edge devices and Internet connections.