There is no Radio Button option in the Legacy Tools section (which you do reach via ALT+L,N). The Radio Button is in the ActiveX control section and it is noted as "Option Button" while what most of us would call a button is noted as "Command Button."
The direct key sequence for an ActiveX radio button is ALT+L,N,O (Option button) and for a command button is ALT+L,N,U
I personally hate the ActiveX controls and avoid them, but others love 'em. All of these announced, item by item, if I right arrow through the Legacy Controls Group then transition into the ActiveX controls group once the end of the Legacy Controls has been passed when I'm using NVDA.
Brian - Windows 10 Pro, 64-Bit, Version 20H2, Build 19042
There are many who labor under the gross misapprehension that the Constitution is a cage and a laundry-list rather than a framework upon which great things have been and still will be built. Many things that are entirely Constitutional are not "in the Constitution," but are allowed under it.