I think they’re amazing, your understanding of color and your style in general. I would love to use the first image as a profile picture.
But since they are detailed and use smaller outlines compared to the image size, especially the second image, the details can get lost in resizing since profile pictures squeeze them into less than a few hundred pixels. I’d suggest using thicker outlines, and feel a little more flexible in using the entire space just for the head. Hope this helped