Use Delivery Plans for dependencies and a team dashboard for metrics. Delivery Plans is not a dashboard widget, but the dashboard can include Velocity or Burndown and Query Results backed by a direct-links query for Predecessor/Successor relationships.
Azure Boards has no native dependency accept/reject action. Add a custom Dependency Decision field with Requested, Accepted, and Rejected values through an inherited process. A custom state mapped to Proposed or In Progress remains on the backlog. If rejection means Team B no longer owns the work, move its Area Path back to Team A or transition it to the Removed category. Removed hides it from backlogs and boards; Completed incorrectly implies delivery.
Prefer a separate Team B work item instead of transferring Team A’s original Feature. Link them as Predecessor/Successor so each team owns its area and iteration without disrupting the requester’s backlog. Surface the decision field in the Query Results widget.