Earlier quoted context omitted.
Not dongle; docking station (old school ones with port on the bottom).
That wasn’t a capability of the laptop. The docking station had its own dedicated graphics hardware that drove the extra monitors. Of course the lowest end Macs can do that. When we talk about how many monitors a certain laptop can drive, we mean plugging them in directly to the laptop in some combination of HDMI ports and USB C/Thunderbolt ports.
Here is the chip in my dogshit 2015 Ultrabook I still lug around, it very clearly states that the chip supports 3 displays regardless of how IO bandwidth is distributed on the mobo: https://www.intel.com/content/www/us/en/products/sku/88192/i...