Expand Book Jacket Artwork Seamlessly

Extend book jacket artwork to wider format (image extension / generative expand)
Hi,
I’m an author preparing my novel for print as a hardcover with a dust jacket. I have a finished jacket design that I am going to use, but the artwork is too narrow to fit the printer’s template.
I’m looking for someone experienced with image extension / generative expand to widen the existing artwork on the sides of each panel, extending the sky, fog, trees, field, and fence, so it fits the correct dimensions. Nothing that’s already in the design is to be changed, moved, or redrawn: not the faces, the title, the text, or the ISBN barcode. It’s strictly extending the backgrounds outward.
I have a complete package ready with the high-resolution artwork, exact pixel measurements for each panel, and a reference picture of the final layout.
The deliverable is one PNG file, 9028 × 4096 pixels.
Please include an example of image extension or generative-fill work you’ve done before, plus your price and turnaround time.
Thank you,
James