Thank you for reaching out, and we appreciated the use of our forum and Marketplace.
Q1 - When you say beta test status, I’m not sure what you mean can you explain? We have a beta test option available after all the required information is filled out then you can generate a redirect url to use for your app. Its not a status, but if want to use the app Externally which means you want users outside your Zoom account to use the app then you will need to get the app published. if you do not it will still work but be limited to use within your Zoom account and its users.
Q2 - The limitation is your app being limited to use within your Zoom account
During testing, we’ve been able to let users join meetings without requiring Zoom sign-in — just by entering a display name. In such cases, how does Zoom determine whether a user is considered internal or external to our account? Does this limitation apply only when users authenticate via Zoom?
Also, are there any other limitations we should be aware of when using the Meeting SDK internally without publishing — such as limits on the number of users, concurrent meetings, or API usage?
Yes this is only for the user authenticating, only one users located on your Zoom account can authorize the app for usage. For concurrent meetings the limitation would depend on your account and API usage limits do not change when the app is published.