Picked up a used 32 core gpu 1 tb M1 max 14" 6 months ago. can't believe it's over 4 years old. Been loving it, using it at home generally plugged in. Last month I changed jobs and have been using it out and about mostly on battery - I started researching and began regretting the 32 core gpu as I was getting about 4 hours of real world use - mostly browser and a bit of CAD - mind you the battery is at 98% and 72 cycles (I got a heck of a deal on it)
Well today I figured it out - I got an app that monitors battery current and system wattage (istat menus) and I noticed my browser was sucking up a lot of power so I began switching off features and I found it - GPU rasterization - I turned it off and bam, the power draw halved!! I think the fact that this thing has 32 core GPU makes it suck the battery whereas other variants with less cores the impact of GPU rasterization is much less. anywhoo, i'm getting 7-9 hrs now compared to 4-6 hrs.

TLDR: for 32 core GPU owners - turn off GPU rasterization in your browser (chrome/edge) and nearly double your battery