Microsoft Project
From Help Wiki
Microsoft Project is a project management tool.
Microsoft Project is not part of our standard license set and requires an additional purchase. Microsoft Planner, however, is part of our license set and can also be used to manage projects. For more info see: https://support.microsoft.com/en-us/office/when-to-use-microsoft-project-planner-to-do-or-the-tasks-app-in-teams-8f950d32-d5f4-40db-a8b7-4d1b82b55e17
If after reviewing this info it seems clear that you in fact need Project, we can move this request over to Purchasing, but keep in mind you will need to purchase a Project license for all of your Team members to update tasks assigned.