I want the the key to right of space which has AltGr written on it (the output of xev is however Alt_R) to perform the the same action as backspace. I tried almost every random combination of setxkbmap backspace:ralt i could come up.
PS: I am running i3 on Lubuntu.
localectl list-x11-keymap-optionsto see the available options instead of trying "almost every random combination". If you can't find an option that does what you want you'll have to write a newxkboption.