M3 Simultaneously supports full native resolution on the built-in display at 1 billion colors and: One external display with up to 6K resolution at 60Hz

M3 Pro 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 over Thunderbolt, or one external display with up to 6K resolution at 60Hz over Thunderbolt and one external display with up to 4K resolution at 144Hz over HDMI One external display supported at 8K resolution at 60Hz or one external display at 4K resolution at 240Hz over HDMI

M3 Max Simultaneously supports full native resolution on the built-in display at 1 billion colors and: Up to four external displays: Up to three external displays with 6K resolution at 60Hz over Thunderbolt and one external display with up to 4K resolution at 144Hz over HDMI Up to three external displays: Up to two external displays with 6K resolution at 60Hz over Thunderbolt and one external display with up to 8K resolution at 60Hz or one external display with 4K resolution at 240Hz over HDMI

See also: American Airways absolutely refused to fly me first class when I only bought a cattle-class ticket. No, I didn't read any of the fine-print, but my ticket cost a load of money. American Airways need to fix their substandard product.