Screen Edge - shortcut addon.

Hi, all,
I am looking for addon which can add some virtual side buttons as shortcut function keys around the edge of the screen during full screen mode reading.

Before I updated my Likebook Mars from Android 6.x to 8.1, I installed one from the Boyue App Store. I know recently that app store is not available anymore. I am looking for alternative.

When I do reading in full screen mode, any quick way to access

Function keys
(1) "Refresh" the screen to remove "GHOST"
(2) Back to "Home" screen
(3) Open the "Background Management" screen

Thanks in advance for your help.