Besides the trunk socket (X98) already discussed, which is tied to the two sockets on the rear end of the front center console, for the back seat passengers (X104 & X105), the only other one is in the front ashtray, center console (X17), which is run of a 20A Fuse F50, which is controlled by the Z44_1 Terminal 30B relay, which your USB is ties too as well.
In short, your G12 has no 12VDC socket that doesn't have a relayed battery source. The only way to have direct battery connection is to wire it yourself, which you could just buy a socket from Amazon, like this:
https://www.amazon.com/YCIND-Termina...zcF9hdGY&psc=1