Every year I have the same problem, but now I know two distinguishing features of the males that will help next time I am confused: The male purple finch does not have dark striped feathers on its underbody and it has light feathers at the outsides of its eye.
Now I have to study the differences between the females!
https://youtu.be/0HeZTYewqyg
The RX10iv isn't at its best at ISO 1600, and this photo was underexposed because of the bright sun at the right which is mostly cropped off. I use DxO Photolab to denoise, apply a few other settings then tweak in Photoshop. DxO's denoising really left so good detail.