Discrete GPU or not does not matter.
Apple silicon seems to work well with integrated GPU.
What does matter is to take a look inside the Surface Laptop 7 15 Snapdragon:
It makes clear that this is not a computing device, but rather a noise generating device with computing functions. 
This is fundamentally different from the MacBook Air.
Can also see it in noise level measurements (dB(A)):
MacBook Air is always empty (noiseless).
(Source: Notebookcheck)
Regards
Guido
JPEG developer