Since it seems like a regular procedure on longer flights that inner tanks feed all engines until quantity on all four wing tanks become equal, why does it lack some kind of auto mode that might be armed to switch off override tanks at the required condition with a ping/notification on ecas? The pilots are always there to do this but since there are many other things that are handled by automation why leave this to be done only manually?

Because the override pumps are also used to correct imbalances.  If you put an automatic feature in it then you need to have a Manual/Auto button to the whole mix. Why bother.

The way they have it setup now is actually simplistic.  It had its automatic features where it needs it and notifies the flight crew when pumps need to be turned off.