Method 1: Button Mapper app
The Button Mapper app is a freely available app that remaps the buttons as the title suggests. Recently this app has announced the support for motion gestures of Google Pixel 4. The app detects Motion Sense via logcat to allow you to set shortcuts to that gesture. The swiping gesture has the best rate of success so swiping left or right gives you a better experience. There are somethings that you need to keep in mind to make this app work perfectly. First, you have to turn on the motion sensor feature in the settings and the “Reach to check phone” option should be enabled as well. You have to give some permissions to the Button Mapper app to wor perfectly. The Button Mapper lets you use the motion gestures even when the screen is off, on the lock screen and on the home screen. These gestures won’t work when there is another app running on the screen. Download Button Mapper
Method 2: Tasker app
Tasker is another app that lets you remap the app but you have to buy the Tasker Pro from the Play Store to completely remap the gestures. Below are all the steps to remap the motion gestures using the Tasker Pro app. Download Tasker Pro
Conclusion
Now you can map the gesture according to yourself on your Google Pixel 4. These are just limited by now but there might be more apps in the future to completely remap the gestures to whatever you want.