On one phone of mine that is running Android 10, I installed Nova Launcher since I like the things I can customise. One thing that unfortunately happened after setting Nova as my Launcher/Home application, is that I lost the Gesture Navigation, and was reverted back to the standard 3-button navigation.
To my dismay, in Android 10, only 2-button navigation or 3-button navigation is available when using a 3rd party Launcher/Home application. This and the background are also mentioned in the help pages of Nova Launcher.
Fortunately, there is a way to activate the Gesture Navigation by the use of Android Debug Bridge (
ADB). This requires you have
ADB installed and a connection authorised.
adb shell cmd overlay enable com.android.internal.systemui.navbar.gestural
adb shell cmd overlay disable com.android.internal.systemui.navbar.gestural