Sadly we adopted Microsoft O365, SharePoint, Teams. How can you organize the org effectively is beyond me, how does MS do it? Are they actually using their own tools they sell others?
In our org, some departments/teams/sites have just a SP, Others have a teamspace with separate SP/document store.
Worse, any meaningful file structure/hierarchy you come up with gets sabotaged when new channels are created as they automatically introduce new folders. You cannot bind a teams channel to a separate folder in a SharePoint. Also, We have private project teams springing up and large fragmentation of information. If you do not know that a certain project space was set up you cannot find or join it.
Going with a "single Teamspace" for the whole org doesn't work either without being able to have nested channels/groups. The org is too large and complex.
I'd love to have a gitlab style handbook to be used in our org to organize knowledge and information, but I do not know if and how it could be set up technically.