@BTr i still hardly understand anything ... And i think you do not understand how recalbox works.

Remember the buttons are named according to the snes layout. If you dn't respect it, of course it can't work properly.
Second, core remaps just remap libretro buttons, not your pad itself
3rd : why the heck use a keyboard ???
If you follow these rules, consoles work perfect. Arcadr is a different different story