How would I select just the faces with the wrong normals? (see pic)

[DNorman]

This addon can nearly do it, it lets you hide the back-faces in edit mode:

[Addon] Backface hiding

[Untitled-1] Thank you Thank you Thank you ! Now I have edited it so that it just works ! This add-on now just works without the visual bloat, thank you ! It just works now and get out of your way ! No third fourth and future fifth button, just two, simple, straight to the point and it just works. THANK YOU @ChameleonScales !!! If anyone want this modified two button no nonsense version, download it here: BackfaceHiding.zip (6.5 KB) When you click show, all hidden polygons will be shown …

Once you have hidden them hit Alt H to unhide and they should be selected, you can now do Mesh-Flip Normals.
(do not use the addon’s show faces option as it will not select the faces you hid)

It is not “perfect”
I tested it on 2.93.1 and it will not hide all of them depending on the angle, this is due to perspective it will hide the back-faces visible in orthographic view from the viewport angle (even if you are in perspective view)