How to obtain the angular based betweenness using free sDNA toolbox in ArcGIS?

The table above shows results of a Euclidean analysis. If you run sDNA Integral again setting Routing and analysis metric to ANGULAR you will get a similar table that includes Betweenness Ang Rn. (This is the same thing as the abbreviated "BtA Rn", which you will see if you set ArcGIS to show you field names instead of field aliases).

I noticed you've also selected Betweenness is bidirectional, I would uncheck that unless you need flows in both directions to be output separately (they'll be identical in any case unless you have asymmetric weights or an asymmetric distance metric). You may wish to compute some radii smaller than n as well to localise the betweenness.