Azure DevOps doesn't provide a native view of the critical path. In part, as Agile methodologies favor a Minimum Viable Product (MVP) over Critical Path Management (CPM). By using MVP, you identify the shortest path and dependencies by prioritizing epics, features, stories and tasks.
That said, we recommend that you use Delivery Plans to view dependencies and a calendar view of work.
If your organization supports connection to Microsoft Project, you might find more Marketplace extensions that support connection of Azure DevOps to Microsoft Project.
For more context, see The Critical Path on Agile Projects and Running a lean startup on Azure DevOps.