The problem that affects everyone is the complete non-standard dimensions of the header images for your social networking accounts. The sizing is different from one platform to another.
For BlueSky, the header dimension is a bit different in how you build it out.
The entire canvas size is - 2048px by 2048px
The viewable area that you will see within your account and others is - 2048px by 512px centered both vertically and horizontally.
The example below should help visualize the usable area that is seen, everything within the red border rectangle.
