When adding a new column to Files tab, disabling "Add to all content types" not working as expected

DougAtBHB If you go to the SharePoint site you'll see that each channel's files are stored in folders within the same library, so if you add a column to the list then it will appear in all folders.

Content Types are a fairly advanced feature in SharePoint that allow different fields for each document, but it's not just a simple answer to your requirement, all the files in each folder would need to be different content types. By all mean go and learn more about content types and try but I wouldn't bother.

I would go to the SharePoint and add a second document library and add the columns you want, then add a tab to your channel to show that document library alongside the Files tab.