This is how this will look like in the end:
Swiping up will work on any screen in any situation
To get this project download the attached file.
First you need to run the Bottom Swipe Setup task in Tasker to create the 3 overlays at the bottom.
In this example swiping the back button will open a bottom buttons screen, swiping the home button will bring up AutoVoice Recognition and swiping the app switch button will bring up Solid Explorer.
To change what each swipe does, edit the task in the React To Bottom Swipes profile and change the actions inside each If action.
Important Note: some users have reported that swiping from the bottom is not working on their devices or that it's not responsive enough. If that's the case you can always use the default side swipe if you need to.

Bottom Swipe Quick Actions 2017-07-13
Create 3 quick actions that are always available by swiping up on the navigation buttons