First, a huge thanks for having read the Welcome Message and having done some digging!! From what you are saying, this is not really an NVDA question, but is related to Windows 10. The solution, based on your description, is using WinKey+B to throw focus to the System Tray portion of the Notification Area, then right arrowing to the control for that toggle and activating it when you wish to toggle character sets. If the toggle button happens to be hiding in your overflow area, then activate the notification chevron and up arrow or left arrow through the buttons that reside there until you find that toggle, and activate it.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
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