Can someone please help me use the Key Adapter setting to setup a custom button configuration so I can play Magic Arena (Magic the Gathering Android App) using the buttons and joystick on my Retroid Pocket 6?

Can someone please help me use the Key Adapter setting to setup a custom button configuration so I can play Magic Arena (Magic the Gathering Android App) using the buttons and joystick on my Retroid Pocket 6?

This is extremely unintuitive for me and I could really use some help.

I want to play MTG Arena on my Retroid Pocket 6 but I don't want to just use the touch screen. I want to use the right joystick like a mouse pointer, I want to use the R1 button as the mouse click, I want to use the A button to select buttons like "Confirm" or "Resolve" or "End Turn", I want to use the X button for "All Attack".

I'm confident that accomplishing something like this has to be possible but I can't for the life of me figure it out. There aren't many video guides on using the Key Adapter button configuration option, but the few I saw were for mapping FPS shooter games which play very differently so it isn't really applicable.