I just set this up since it was such a good idea.
- Go to Settings->Safari
- Click on Downloads
- Choose Other….
- Navigate to the top level of Files and select On My iPad
- If you don’t have Download folder, click the Folder+ button at the top of the window and create it.
- Go to the Shortcuts app
- Hit the + button at the top of the screen
- Name the Shortcut Downloads. Choose a file folder icon by clicking on the default icon and tap Glyph->Objects and scroll to find the icon
- On the right pane, chose Documents
- Click on Folder
- On the left pane click on Folder and choose On My iPad->Dowloads
- On the right pane choose Scripting->Open App
- On the left pane, App, Choose Files
- Click on the top the control icon And click on Add to home screen
- Name the Shortcut Downloads
Now on the Home Screen, click on Downloads and the files app opens to the On My iPad->Downloads folder