Back in Android 11 DP2, separated back gesture sensitivity settings first popped up, claiming to tweak how the edge navigation gestures worked. At the time, we weren't sure if the new settings actually worked, but as of DP3, it seems like they do. 

Android 11 DP3 includes expanded sensitivity settings for full-screen gesture navigation, allowing device owners to customize how easily the back gesture activates for either side of the screen. On Android 10, there was only one sensitivity slider, which affected both sides of the screen equally. The new options were present in the first Developer Preview, but until now, they were non-functional and could only be opened with ADB or an activity launcher.

Left: Android 10; Right: Android 11 DP3

While the full-screen navigation still isn't perfect (I still use the three-button nav wherever possible), it's nice to see Google continuing to make iterative improvements.