Can this be used in the non literal sense: "I don't know who supports me"?
Yes. As one would expect it's an uncommon euphemism and not many people would understand it.
Thanks a lot you two :)
Could this also be translated as "I don't know anyone behind me"?
that's what I'm thinking too
The audio for ở phía sau is super fast... sounds like a robot talking too. Can we slow that down a bit?