From my understanding, other than core count, the GPUs should be the same between MacBook Pro and Air models with the same model of chip (base, Pro, Max, Ultra).
At one point I read a die analysis which suggested that total monitor support was tied to the number of hardware components within each model of chip (two for base, three for Pro, etc.). I believe it is a new feature of the M3 (base) MacBook Air to allow two external monitors to be utilized when the internal display is off via clamshell mode, but perhaps this will come to the MacBook Pro as well via a firmware update.