How can I get the _real_ progress of dd, ignoring fast/staging buffers?

I'm using the dd command to write to a USB stick. My command is pretty straightforward:

dd if=myimage.iso of=/dev/sdd bs=1M status=progress

and indeed, I seem to be getting the progress reported:

1234567890 bytes (1.2 GB, 1.2 GiB) copied, 15 s, 101 MB/s

... but after a few seconds, I'm told that the full amount of data has been copied - without dd actually concluding. Likely, the data has been written into some temporary buffer (in memory perhaps?) - but the process of physically writing it to the USB drive is ongoing. Only when it is actually done, does the dd command return. Is there a way to obtain the real progress, in terms of amount of bytes really written and/or estimated time remaining, for such dd executions?