Apparently I'm off the end of the chart. My last workplace set up had:

• primary 15" laptop with two external monitors (so 3 screens in use simultaneously)
• secondary 15" laptop with external monitor (so another 2 screens) when the primary one was tied up doing heavy processing (I was lucky and managed to hold onto my previous laptop when we did the usual rounds of device upgrades whereas most people just returned them to IT to be retired, so I had a spare that I could readily take home for WFH days without messing with my main office setup)
• a standalone PC monitor (for automation stuff, so the screen was there just for monitoring as needed)