Stylize this pdf, convert to Adobe Express and edit images in Adobe Express are missing

Hello, I am learning Adobe Express and Adobe Acrobat Pro and own a Creative Cloud license. I want to use the features to edit and style PDF files in Adobe Express. But the functionality is missing for me. Because there are several similar posts here, I tried to follow the solutions and tried different PDFs created with Acrobat and Adobe Express. And I tested with Englisch and German as language configured in Adobe Acrobat. And I watched several videos explaining these functionalities. But the functionalities are still not available for me in Acrobat Pro on my MacBook and also not in Acrobat Web.

Thank you very much for your help,
Jens