In Bigbox go to options/image cache and "refresh platform logos". Also its worth noting the logo must be named exactly the same as the platform is named in launchbox/bigbox.
Launchbox doesnt have a "core list" the dropdown just shows the cores you have in your retroarch/cores folder. So if a core isnt showing, you dont have it downloaded in retroarch.
You really think a ARM based notebook will be anywhere near as good as a desktop PC? That's dreamland you are living in there. Somehow i dont see a ARM based GPU worrying my RTX 2080 Super any time soon.
Well the point is as Jason said in his original post, that emulation in general may no longer be possible on Android full stop. Short sighted would be continuing to invest time and money into a platform, that come the next release of Android may no longer support the functions that a frontend requires to actually be usefull.
The fullset importer assumes you have a fullset and adds all working games, regardless of if you have them or not. It doesnt actually scan and check your files as its specifically for fullsets.
I use one of these, it supports xinput, dinput, macOS and switch.
https://www.amazon.co.uk/8Bitdo-Wireless-Bluetooth-Nintendo-Raspberry/dp/B01ND166P6/ref=sr_1_6?dchild=1&keywords=8BITDO&qid=1588415360&s=videogames&sr=1-6