owners vs site owners vs members vs site members vs access to site content

Hmm, I will try to explain this as good as possible.

There are differences between a SharePoint Team site and a SharePoint Communication Site.

For a Team site,
You should just rely on the Owner and Member SharePoint Groups. The reason for this is that it is synced with the membership in MS Teams. This ultimately affects the document libraries because they are also created through channels.

This gets extra tricky with private channels and shared channels, because they create a separate site/space.

For Communication sites,
In Communication sites you do not have "Owners and Members". Instead, it is only Site owners, site editors and visitors.

Yours sincerely,
Aref Halmstrand

Please mark as resolved if this was helpful 🙂