I could see opting for a 15/16” machine with no dedicated GPU, simply because the size of it means the cooling system is likely large enough to keep the CPU at reasonable temps without keeping fans spun up the vast majority of the time.
For a short while I had a 15” laptop with a high power AMD CPU and high power Nvidia GPU (5900HS/3080) and while the power was nice, it was much more noisy and hot than I prefer in a laptop so I returned it. Now if I need graphical muscle I turn to a tower, which can provide that in vast quantities with a fraction of the fan noise.
My laptop (Lenovo legion 7) has a vapor chamber cooling system is shared by the CPU and GPU, so when you're only using the CPU it will have the full cooling power of the laptop.
For a short while I had a 15” laptop with a high power AMD CPU and high power Nvidia GPU (5900HS/3080) and while the power was nice, it was much more noisy and hot than I prefer in a laptop so I returned it. Now if I need graphical muscle I turn to a tower, which can provide that in vast quantities with a fraction of the fan noise.