I've had to switch to linux full-time on my latitude for precisely this reason. It sleeps perfectly and the battery life is a lot better on linux than on window

I've had to switch to linux full-time on my latitude for precisely this reason. It sleeps perfectly and the battery life is a lot better on linux than on windows. The good thing about Dell is that they ship with linux on certain configurations, so linux installs are very robust with the caveat that you will not see the agressive fan curves or higher tdp limits that you can get on windows.