Sorry, I have a similar question concerning multiple external displays with the 2021 14 and/or 16 inch MacBook Pro. Despite many hours trying to find the answer on Apple's website and others I am still in the dark. Based on my reading on the web, I'm not the only one.
The new M1 Pro and Max SOCs seem to be wonderfully innovative -- that also means that it is risky relying too much on experience with previous Macs. It would be very helpful if the details of which configurations, such as external monitors, could be explicitly described. The question asked by the OP above is a good one and as far as I can see is not addressed in the reference provided.
For example, the reference states:
If you're using a Mac with M1 Max:
- You can connect up to four external displays to your Mac using the Thunderbolt 4 (USB-C) and HDMI ports.
If you're using a Mac with M1 Pro:
- You can connect up to two external displays to your Mac using the Thunderbolt 4 (USB-C) and HDMI ports.
The tech spec for the MPB states:
Video Support
Simultaneously supports full native resolution on the built-in display at 1 billion colors and:
- Up to two external displays with up to 6K resolution at 60Hz at over a billion colors (M1 Pro) or
- Up to three external displays with up to 6K resolution and one external display with up to 4K resolution at 60Hz at over a billion colors (M1 Max)
Thunderbolt 4 digital video output
- Native DisplayPort output over USB‑C
- VGA, HDMI, DVI, and Thunderbolt 2 output supported using adapters (sold separately)
HDMI digital video output
- Support for one display with up to 4K resolution at 60Hz
- DVI output using HDMI to DVI Adapter (sold separately)
Does this mean that:
- A separate output (Thunderbolt/USB-4 or HDMI) must be used from the computer for each external monitor -- that is, no daisy changing or hubbing even with Thunderbolt?
- For the Max, the fourth external monitor must use the HDMI port?
- For the M1 Pro, the second external monitor may use either a separate Thunderbolt/USB-4 port from the first monitor or optionally the HDMI port?
Thanks and congratulations to Apple for inventing such an exciting new advance in computing and thanks in advance for any clarification on these questions.