Nah. You have to enable the "All Gestures" setting by yourself. Now you will see that there are three settings available, instead of two like on Android 9 Pie.
You have the classic Android navigation buttons, the pill and back arrow and the new Android 10 getures. (You have to go to "System" in the Settings" to find the gestures, the shortcut to gestures that you could get when pressing directly on the home screen is fine.)
And if your Security Patch has gone back to the November 2019 one (happened to me) go back to Systems and check your software update. The December Security Patch is there and you'll have to download it separately.
And yes, so far my battery appears to be going much faster...
As for the system wide Dark Mode, my Gmail and Google feeds are not yet supported so they are still white/light...