What is the best intelligence gathering/sharing project management platform?

I think Notion should be able to cover everything you're after. Have you tried using it?

Explore GanttPRO. The tool helps in planning work, tracking tasks, setting deadlines, and collaborating with stakeholders. It empowers to create unlimited projects and work with unlimited resources, even using a free trial. You can use it for software development, construction, healthcare, events, human resources, and other spheres and industries. A Gantt diagram provided by GanttPRO allows for scheduling activities, setting dependencies, adding milestones for project tasks, and working with flexible WBS hierarchies. You can prioritize tasks to make sure deadlines are met. Its integration options make it a powerful project management suite. There is also a useful functionality that allows you to import MS Project files, .xlsx files, and .csv files directly. Exporting is also available here. Follow the site to get more details (https://ganttpro.com/).