The question really depends on what this "guest" account needs access to in the dashboard and your intentions around the account.
Traditionally, any user created to access the Meraki dashboard is some sort of Administrator.
Access can be limited to specific networks or full organisation.
Permissions can be read-only or full Administrator.
You can do all this from the Organization -> Administrators page.
There is an early access for RBAC now which provides more granular controls
Managing Dashboard Administrators and Permissions (Modernized View) - Cisco Meraki Documentation
