OneLake:
OneLake is tailored for integration within Microsoft Fabric, a data platform designed for constructing lakehouses and warehouses. It provides a cohesive and centralized data lake solution spanning an entire organization.
If you require a unified data lake that encompasses robust features for governance, management, and analytics within the Fabric ecosystem.
ADLS Gen 2:
ADLS Gen 2 serves as a standalone data lake storage solution within Azure. It allows the creation of multiple ADLS Gen 2 accounts to cater to distinct projects or teams.
If you need a flexible and independent data storage solution within Azure, capable of handling your own data management and integration needs.