I've connected 4 external monitors using two cheap USB-C port expanders. Each of those has 2 HDMI, 1 DPort, 1 Enet, and 1 USB-C. At the moment, I'm using only the 2 HDMI ports on each device. I am able to extend the laptop screen to any four monitors, including the laptop internal display, but the fifth one is always greyed out and can't be dragged.
I'm guessing that the onboard Intel Xe Graphic chip is what limits the number of displays to 4.
Would a more elaborate port expander fix that issue? Maybe something with a GPU built in?
I've heard the term "alt mode" for DP ports. Would it help if I used the two Display Ports instead of HDMI?