You have precisely described my experience with my latest laptop. I get probably 4 hours of battery life in this mode. After that my battery is probably at 20% or less which means that when I open the laptop there’s almost nothing I can do with it.
I had to figure out how to re-enable S3 sleep and now I’m struggling with my stupid Wi-Fi adapter which breaks every time I resume from sleep but all I have to do is toggle it and I’m back to running again. After doing this change my battery life in sleep will actually last at least a day now which is massive compared to what it used to be.
Glad I can shove more things into the same physical space. I can’t wait until HAMR is ready next!