Is there any way that you can limit a tab to certain user/users so I can make a admin change from the app instead of everyone seeing that tab?
No, you can’t control which tabs are visible based on the user. What I would do is have an admin tab in the hamburger menu. Use the detail style layout. The sheet for that tab would only have rows for the administrators with their email. Turn on email filtering and then you can add any components or inline lists that only that administrator could see. The tab would be visible in the menu, but a non-admin would not see anything inside the tab since there would not be a matching row.
In my app I have a settings option in the menu that’s available to all users:
Using relations, I currently have 2 inline lists with only one related item each. Only those emails that have a value in the administration column to link to the admin sheet will see the admin option.
This screen is only accessible to those that have admin rights.