Fix Squarespace Mobile Navigation Usability

Greetings,
I am building a photography portfolio website using Squarespace to showcase my photographs. The site is fairly simple—there is no e-commerce, blogging, or event functionality—and I am satisfied with how the desktop version looks.
Where I have been struggling is with the mobile version, Mobile-responsive design. It does not display as well as I would like across different screen orientations, there is quite a bit of unnecessary empty space on some pages, and the overall mobile experience does not feel as polished or user-friendly as the desktop version. I would also like to improve how visitors can view and interact with the photographs on mobile devices, including landscape and portrait viewing and, if possible, better image zooming or expansion.
I am looking for a quote for focused assistance with the mobile version rather than a complete website redesign. Photography is a personal hobby rather than a business for me, so I am trying to keep the scope and cost reasonable, but I am certainly willing to pay for professional help to get the site looking and functioning the way it should.
If this is something you work with, I would be happy to provide a link to the site and any additional information you would need to estimate the work.
Thank you,