Capture Audio line In to Mac Book Air 2024

My Goal

Simply to record an audio line directly into a mac book air running Sonoma 14.5

I have a headphone splitter coming out of my piano's headphone jack. I have split this to my headphones and to the computer tin hopes to record what I am hearing in the headphones. This ain't MIDI.

I would like to record the audio in either Garage Band, or Quicktime, or something similar. Just need the computer to recognize the audio.

Here is what I have attempted.

I have used a direct headphone jack right into the headphone port - And tried to switch it to an input. That wasn't an option. This doesn't work.

I have used a converter from headphone jack to a USB-c into the computer. This shows up, but It only recognizes the USB-c as an output device. SO this also doesn't work.

The plea for help!

Does anyone have a solution that wont cost me money to buy some extra hardware to do a simple task? I sure would appreciate it!