Your profile picture has a different job from your channel banner. It needs to identify you beside comments and videos, where there is little room for detail. A whole studio, a distant person, or a full business sign may look interesting when opened but become an indistinct patch in the interface. Start with a close portrait or the simplest version of your mark.
YouTube's profile guidance describes an image that renders at 98×98 pixels. The 800×800 output selected here is our working export, not a claim that YouTube displays every uploaded pixel. Leave space around hair, ears, or the outer shape of a logo so a rounded presentation does not remove something important.
Avoid relying on a long channel name inside the artwork. If the initials are the identity, make them bold enough to read without zooming. A recognisable silhouette and clear separation from the background usually contribute more than increasing the pixel dimensions of a complicated design.