WORDPRESS MULTISITE
Choose the scope.
Then connect the storage.
A network connection and an individual site connection are separate. Always check which administration screen you are using.
Network setup
Open Network Admin → Settings → Stateless Connect. The screen identifies network scope. Configure the shared connection and storage policy intended for the network.
Individual sites
Open the site’s own Media → Stateless Connect screen when separate site configuration is allowed. Review inheritance and any network-controlled settings before connecting.

Before rolling out across a network, test two sites, their upload paths, root directories, and generated image sizes. Confirm that one site’s cleanup does not remove another site’s media.