Hi zilvart, skipping details that you said that weren’t your objective, I’ll shoot my thoughts.
Your drawing cause a different impression. That is totally subjective from person to person, but what makes the difference is the color combination and the contrast of those. The dark/red (with some orange to simulate flames) differ from your orange selection. That plus the softer black cause a softer mood in the character. Remember red= passion, danger, etc. Orange remembers me to a warm sunset.
Also look at his mane and his back. There’s an obscure zone creating like a dark aura to reinforce that threatening looking.
I hope I said something you didn’t noticed, and good luck with your studies
PD: Ignore the ratting, they are invented (yeah 5 originality lol). I cannot rate technique bc of going to the important stuff you wanted to learn...