SharePoint 2019 Modern List - the request message is too big. The server does not allow messages lar

I am migrating a site from the classic SharePoint to SharePoint 2019 Modern Site.  As I have been moving documents, I came across a problem uploading a 56mb document.  The error message I receive is:

The request message is too big. The server does not allow messages larger than 52428800

If I change the list experience back to classic, I can upload the document but as soon as I move it to the modern experience, I get the error.

Obviously, the easy answer is to change the list back to classic and upload all the document and then change it back to modern, but that doesn't fix it for the next time the user tries to upload a document.  The web application has an upload size limit of 1024 so that isn't the problem.  It seems to be a problem with the modern list experience.  

I've searched around and the only reference to this is for people trying to upload documents with code which I am not doing.  I am using the user interface.

I'll keep searching but if anyone has any answers, I'd appreciate some help.