Acrobat Pro Whites Out PDF Content - not visible
I am running desktop Acrobat Pro on a 2023 Macbook Pro (Sequoia). I have a document that I have worked with for a long time, but I can no longer see most of the content in it. I can see the content when I work in Adobe.com, but not on my desktop app.
I have removed the checkmarks on smooth line art and smooth images, but that doesn't fix the issue. My use of Acrobat Pro is fairly limited to reviewing and minor editing of documents, so I am struggling to understand the problem. Can anyone help?
I can't upload the document here due to work restrictions, but below is a screenshot of the issue:

