I've got an MSI laptop and I've settled on simply never using the Nvidia card (prime-select iGPU only). The integrated graphics have access to 16gb of ram (versus the Nvidia card's 4gb) and deliver better performance without the whole laptop hitting 100 degrees.
I hope the Asahi Linux project succeeds so I can buy the fabled Apple silicon laptops just to run Linux on them.
I just double checked the firmware setup and it seems I was misremembering things. There's a toggle between "DISCRETE" and "MSHybrid" which means dGPU only and hybrid iGPU + dGPU graphics. I use it in MSHybrid mode with nouveau drivers. This keeps the dGPU in the lowest possible power mode.
It still wastes around 7-15 W doing pretty much nothing according to my monitoring script. That's the entire power budget of a single board computer like the Latte Panda Mu.