I wouldn't worry about the annoyance of that initial message too much, doing things this way has become very common. Games like Brok the Investigator and Code 7 both have a spoken announcement how to turn on the screen reader with one shortcut on first launch, while games that initially launch to a more expansive accessibility menu like the Last of Us also come up with the screen reader talking until you either select the vision presets and leave it on, or close out of the menu at which point it'll stay off.