Delete key under iOS with Microsoft Universal Foldable Keyboard

Question

I use the Microsoft Universal Foldable Keyboard with an iOS device (iPhone SE running iOS 10.3.2). I am trying to get the Delete key to work.

I read on this data sheet that with the iOS key binding, Delete can be used by combining Fn and Backspace. However, in iOS mode the Fn key is mapped to Cmd, so that pressing Fn/Cmd and Backspace at the same time causes a "delete the current line" rather than a proper "Delete" for me.

Any idea on how to get this to work? Many thanks!