From the independent battery tests I've seen the battery life should be noticeably better. Did you take a look at Activity Monitor to see if something is using high CPU?
>...From the independent battery tests I've seen...
> In our video rundown test, the 14-inch Pro lasted even longer, crossing the 30-hour threshold, becoming the longest-lasting laptop we've ever tested.
In this video they compare the M2 Pro and M3 Pro and the M3 Pro has more battery remaining at the end of the video: https://youtu.be/aQvsZQ3QBiU
Same for this video where they compare M1 Max, M2 Max and M3 Max: https://youtu.be/BWeuhxnWDl0
I'm seeing a bit better battery life in general on my 16" M3 Max than I did on my former 16" M1 Pro.