FWIW, in my opinion, you definitely have shown a steady improvement. However, if you want to emulate a classic pro portrait, there are a few aspects of the image that jump right out at me, and not in a good way:
1. The patch of white sky behind you is, IMHO, almost a classic textbook example of exactly how to lead viewers' eyes away from the subject.
2. Your eyes sockets look dead and sunken, and there are no catchlights reflected in the corneas . A tiny touch of fill flash (say, 1.7 stops down from the main exposure) would have taken care of this in-camera.
3. The overall brightness (particularly, skin tones) is still quite a bit lower that I think appropriate.
4. There still is too much unevenness to your skin tones, both w.r.t. color (eg, areas of overly saturated reds), and w.r.t. tonality (eg, reflective hot spots, deep shadows, etc.)
5. The framing of the image is too loose for a classic head and shoulders portrait, and it's not even close to the standard 8x10 (or 4x5) aspect ratio for portraits / headshots - it's much too tall - too much wasted space.
Below, I've tweaked you last version to illustrate the sorts of changes I would make if this were my image. I intentionally exaggerated my tweaks to make them easy to see, but it's almost trivial to blend back in a bit of the original to achieve a more gentle treatment. BTW, I decided to go with a nearly square crop just to contast with the very tall crop you had.
Cheers,
Tom
PS - Don't forget that all photos (particularly the shadow areas) look unusually bright on iPhones, iPads, etc. because of Apple's design decision to try to make average photos look a bit better versus giving the user a strictly accurate, but not very flattering display.