USB Mod For Sony XAV-AX100 for 2011 Prius

So I have a base model Prius Two I just bought off of my dad.

The first thing I wanted to do was get a double din head unit with video so I can add a backup camera and run my phone etc via bluetooth. For ease of access when I want to charge my phone, etc and directly connect to the head unit I wanted to extend the USB connection off of the back of the stereo to somewhere I can get to in the car. I found this instructable where the guy cuts the blank where the seat heater control is on other models and adds a USB adapter. it's my first post so I can post a link but if you search for instructables USB power plugin 2010 Prius III you can see what I'm talking about. I stole the photos attached.



However I want to add a USb extender from the stereo to some sort of USB barrel connector to that slot.

Is there an aftermarket or factory insert that will fit into that blank space that's usually reserved for the seat heaters? I can't seem to find anything and the cut out blank looks kind of janky. Appreciate any and all help - this is my first post. Thanks so far these forums are super helpful.