Did you check USB-C/Thunderbolt Dock Megathread already?
I’ve got the “basic” 7840 FW16 without dGPU, Linux (currently Tumbleweed) and a Dell WD 19DCS docking station, driving a total of three external monitors plus the internal one. No 160Hz or 4k, though. 1920x1200, 1600x1200 and 1027x768 at 60Hz.