Hey there!
Sorry, it's currently not possible to do that dynamically :/
One thing I can think of, is maybe create all the tabs you need in advance, and at Awake/Start, you disable the TabItems you don't want to show for now (located under TabView/Tab Bar/Container/).
And when you want to add a new tab, instead of adding one, you just activate this TabItem, so it will look like a tab has been added.
Maybe this workaround can help you?
~Yohan