About your questions:
My issue is that when I am not logged in as admin, the hero image on the front page dissapears when the page loads. It just becomes a grey box. This happens for all users of my site. What can I do to make sure that the hero image loads for all users?
Can you please disable performance optimization plugins? Then try again.
Most likely that a performance optimization plugin is causing this issue.
If that will be the case, then you will need to adjust it’s settings till the section starts working.