In the South East, they bring you sweetened (usually far too sweetened for my tastes) iced tea. This is amazingly universal.
I live in NC and have been probing the border for years.
For “nicer” restaurants, the universal sweet tea boundary seems to be precisely at the NC/VA border.
Where the hell are you in the midwest that they don’t have iced tea? It’s ubiquitous in my experience.
Not a guarantee here in northern Indiana.