How to best use Planner to keep our department organized

Hi,

If there is already a discussion that outlines this, please feel free to point me to it. (No need to re-create the wheel!)

We need to get our department organized and would like to use Planner to do it. We have four "functional groups" that each have projects they're working on that the other functional groups do not need to see. But, there are some cross-functional project that all groups DO need to see and be part of.

I have two concerns I would like to avoid, if possible:

1. Project/Plan overwhelm, and
2. Silos

I'm curious how other multi-functional groups set up Planner to keep things orderly. (Note: We do not use Microsoft Teams all that much and are simply thinking of using the Planner web application if/when we get it set up properly)

One final thought...are there Microsoft Planner consultants out there who could help? I've tried talking to AI about our needs in order to get a recommendation but don't have a lot of confidence it's giving me the right plan of action. It feels like there are heavy users of Planner who could give me a much more solid recommendation if they had a clear picture of what we're trying to do. Thanks!