Access to the analog audio line input

[Zhivko]

I am a total neophyte in this arena. Please excuse my ignorance.

A friend is trying to replace a Raspberry Pi based design which incorporates a hat with digital and analogue IO pin functionality.

I have been asked to provide some feedback on A64 based single board computer as a suitable replacement.

I note audio line signal path is AC coupled from the connector to the A64 pin.

Is it possible to to remove the capacitor ( short it out )and access the A to D output in order to measure external very low frequency signal?

Is it further possible to process so acquired data and push it out through the DC coupled line out path?

If the hardware can achieve this what software tools are required? C may be? libraries? register bit listing? Kindergarten classes?