I’ve only used the ZeroTier client for iOS, but it’s pretty bare bones. I’m suggesting a few enhancements that would help a small office environment where resources can be frugal.
Similar to the iOS VPN client, the status bar changes to a timer which helps to remind the user that the VPN is connected and running. This helps users to disconnect from the Client services when not in use, saving resources, and providing a minimum level of security.
An enhancement to the status bar timer would be a pop-up reminder where the admin could set the reminder time period, for example 3 hours. After 3 hours a pop-up would say “Connected to ‘network name’, Continue? Disconnect? Remind me in 1 hour”
Add an optional authentification step like Google Auth app code before starting a session. This will help secure saved passwords for network assets on a compromised computer as will as add intention to the connection to prevent accidental network connection.