Not certain but I think you'll need to remove the door card to see which end of the cable is the problem. Guide below looks good.

Either that or use The Dukes of Hazzard method!

https://www.alfaowner.com/threads/how-to-remove-a-front-door-inner-panel-access-lock-or-window-regulator.1175857/

 

Thank you but I seem to recall that a reset can be made via the dash controls. I had previously set the option for automatic door locking

 

Do you mean turning off automatic door locking might help ? I doubt it but try it.

The inside handle will always open the door irrespective of lock or unlock status - unless the deadlocks have been enabled.

 

Has it gone loose or completely stuck solid so that it cannot be moved?

The handles are known for breaking.

 

The handle functions normally but is unable to release the door from the automatic lock setting after the car is driven and I need to get out! I open the window and open the door using the outdoor handle!

 

there's an unlock button on the dash if your car is 2013 or before. But an easier check is see if the passenger door does it too.

I also suspect the handle or cable is broken

 

The unlock button does not release the drivers door but does release passenger door. Handle is good and it feels like the cable is the same as it was. I did see a post here some time ago of a member who was locked in his car but I have been unsuccessful with the searches. I am almost certain that he resolved it by adjusting settings on the dashboard

 

It's a lock issue if only 1 door is affected

 

Open the door and using a screwdriver or metal bar to move the lever in the U shaped part of the lock to simulate the door being closed. Now try releasing using the interior handle. Does that work? If it does it may be that adjustment of the part on the door frame is required. If it doesn’t release the problem is within the door; the door trim is easily removed and there are guides on YouTube. It may be the lock itself. I’ll see if there are replacements available.
Image is of the general arrangement; it’s actually a rear.

 

Update: Looking online the door lock is available in many places. That may indicate it is something that fails often enough for suppliers to have it in stock. Not cheap new but more affordable s/h.

 

Might be worth toggling the deadlocks (2 presses on remote) as their function is to disable the interior handles. Not sure if it can malfunction or stick even when the outside handle is working.