Shared channels in teams are broken

I would like to report several critical limitations affecting the usability of Shared Channels in Microsoft Teams, which severely impact collaboration across EFSA teams.

Issues encountered:

1. It is impossible to install Planner in a Shared Channel, despite the need to manage work jointly with colleagues from other teams.
2. If a Planner plan is created outside a Team, the communication panel/comments are disabled, making it unusable for actual teamwork.
3. When adding attachments to Planner tasks, the document picker does not show the Shared Channel’s document library. It only displays the main Team’s library, even though the Shared Channel creates its own dedicated SharePoint library.
4. This leads to a paradox:
   • We create a Shared Channel precisely to collaborate cross‑teams
     • A new library is generated for that channel
       • But we cannot fully use it with Planner, comments, or attachments
         • This makes Shared Channels appear incomplete and unintuitive.

Impact: These limitations make Shared Channels extremely difficult to use for real project management and cause confusion for end users. They force us into workarounds that break consistency, traceability, and efficiency.

Request: Please escalate this to the product team. We need full Planner integration (installability, comments, attachments to the correct library) for Shared Channels, or an official workaround with timelines. This is a major blocker for cross-team collaboration.