SharePoint Online vs. Microsoft Teams for Project Management and Cross-Site Document Searchability

Hi Doug,

Just a clarification - Teams doesn't come with a "watered down version of SharePoint". It sits on top of Office 365 Groups which includes its own document library, but also comes with a fully functional SharePoint site.
The challenge you have is that each Office 365 Group is its own SharePoint site collection, which means it has a unique set of permissions and in your scenario - you cannot easily search across them.

However you can actually search across multiple site collections in one of two ways:
- configure the Enterprise Search Center
- use the Content Search Web Part as it can aggregate content across multiple site collections

Just be aware that Teams is not a solution simply to get you a SharePoint site. Teams is a chat space with a virtually all-in-one UI to access resources from Office 365 Groups - which is where the real functionality comes from.

Based on what you've said from your IT department, I'm taking the guess (without being rude) that they don't know much about these features of Office 365 because if they did they would have been able to answer your question in the first place but also be able to guide you to the correct solution.
I'd suggest looking to engage an external Office 365 specialist (either company or individual like myself) to help you, IT and the broader business understand the different collaboration options.