I use the left swipe for menus a lot and was really hating the back gesture messing that up. Found https://android.gadgethacks.com/how-to/disable-androids-back-gesture-left-side-make-hamburger-menus-easier-open-0338679/ and worked perfectly. The below ADB code is what I used and assumes you have the Android SDK and ADB set up.
Code:
adb shell settings put secure back_gesture_inset_scale_left 0