The Amanero brd has a Flag for DSD64/DSD128, but not DoP.
Again, I have no experience with that board, but here are some thoughts.
I think that is backward. From what I read, Header 7 is set when DoP is detected. The board needs to differentiate between PCM and DoP and it seems it does so by looking for the FA05 MSBs and sets 7 accordingly.
I am not an Apple guy, but since I believe the board works with usb from an Apple computer, I do not think the DoP determination is made on the PC/MAC side, since there is no special driver for Apple. As far as I know, IOS just thinks it is sending a PDM stream. That means the DoP determination is made on the board, which does not explain why your DoP files are not detected as DoP. There is an old form of DoP which uses a different MSB value. Is is possible your DoP files are using the old format? Can you you look at them and see if they have FA05 in the MSB?
Again, no real experience here, just trying to understand what is going on.
FWI, Vinyl Studio can write out DoP files. I have not tried them, but it has that capability. It is $29 and has a free trial.
Edit - I am assuming it works with Apple. Documentation says no drivers available.
Edit - Found references that indicate that it is supported natively by IOS up to DSD 128, which means DoP. And there are no IOS drivers. So, I think my above discussion stands.