Blackmagic Design will shortly release a firmware update for their Blackmagic View Assist monitor/recorders that will allow you to finally record BRAW from the Sony FX3/ FX3, FX30, FX6, and FX9.
A year ago, Blackmagic Design showed a development concept where the Sony FX9 could record Blackmagic RAW externally. As that was an older camera that has now been discontinued, they went back to the drawing board, and they have been working closely with Sony to bring BRAW recording to some of their more popular cameras, such as the FX3, FX30, and FX6.
The firmware update for the Blackmagic View Assist monitor/recorders will be coming in October for the FX3/FX3A, and FX30.
Towards the end of the year, it should be available for the FX6 and FX9.