If you have an old iPod it's likely you also have some old iTunes purchases. Beware that before like 2012 all songs purchased from iTunes were encrypted and can not be played on anything accept an Apple device. And if you do just dump those on a USB key and the Tesla runs into one the whole music app just crashes. (tried this myself and ran into this issue)
They make little USB bluetooth dongles with aux inputs. Maybe you could plug one of those into the car and sync it like a phone, then plug the iPod into it. Just beware of which one you get. Some have a feature where they can act as both a transmitter and a receiver, and the way they switch is by being plugged and unplugged. So every other time you turned on your car it would be in the wrong mode. Just get one that's transmit only or has some sort of manual switch to change the mode.
I still had this one in my cart from when I was considering adding a Sirius/XM antenna to the car....
https://www.amazon.com/gp/product/B07TLVJWQ5
It has a physical switch for transmit and receive.