Navigation gestures have become quite popular in the last year or so, and in case your smartphone doesn't support them, or you don't like their implementation, well, there's a new app on Play Store that may interest you. The name of this app is 'Fluid Navigation Gestures', and this is a brand new app, it's still in the 'Unreleased' state, which means this is a beta version of the app, essentially, which is something to keep in mind before you download it.
That being said, before downloading this app, you should also keep in mind that your phone will either need to be rooted in order to make it work, or you'll need to connect your phone to a PC in order to grant it system permissions via Adb. Now, in case you don't know how to install Adb, or how to make the change, everything is explained in the description of the Fluid Navigation Gestures app, and it's really simple. With all of that out of the way, this app brings a ton of functionality on the table, as it enables both the phone's bottom, and its sides to serve as triggers for various actions. All of that comes in a really nice package, as a nice animation will follow your action, so that you know exactly what you've triggered, while basically any swipe has a secondary action as well, and the best thing of all is… all actions are customizable.
So, for example, you can set the bottom-up swipe to be your home gestures, and if you swipe up and hold, you can activate Google Assistant, for example. Swiping from the left side of the display to the middle can be your back action, while you can set right-to-middle swipe to be your split screen action. These are only examples, but there are a number of swipes that you can set up, and if you'd like to get a better idea as to how all this works, check out the gallery down below, and the provided YouTube video.