6700XT is still a bit faster than the 7600, I think. Feel free to correct me on this.
Agree on the SSD, while a PCIe4 may not be needed, I'm sure there're plenty of better SSDs than the Intel for cheap at this point in time. The price drops have been pretty good across the board.
I was considering something like this for work. One downside of this approach is that you'll be carrying more weight; with the NexDock it's going to be a 1.6-1.7kg affair for a 13.3" notebook.
Also if you're going to be doing photography, what software are you going to run on the Steam Deck?