Hi,
Thank you for the screenshots.
Yes, I initially checked your first screenshot and provided another screenshot indicating the background image field inside the Page Title tab of the respective menu item edit window.
After checking again, I noticed that you have already assigned an image in the background image field. However, the image filename contains a whitespace, which is causing the image not to appear properly.
Please rename the image file without any spaces (you may use underscores instead), then re-upload the image and select it again as the background image. This should resolve the issue.
Please check the screenshots below for reference:
https://cleanshot.com/share/NRyg0fdb
https://cleanshot.com/share/XXWljQ5z
Best regards,