A "Network" account adds one additional level to the usual setup of display groups within an account - Network users are at the highest level, and can add accounts within the network, in addition to Display Groups within the accounts.
Network account structure adds an additional account level to the typical account setup. In this example, CloudCO is a network and CloudCo West Coast and CloudCo Midwest are accounts inside of the network:
There is no concept of a "limited" user at the network level. By definition, network users have full access to everything within the network.
Standard account users (despite any user or administrator permissions) can only see what is within their account - they cannot access other accounts. If you want a user to be able to access multiple accounts, without administrator permissions at the network level, add the user to multiple accounts inside the network. Once they are added, they can move between the assigned accounts.