A healthy body can be dysfunctional if there is a problem with a single nerve. Similarly, a machine stops working even if a minor component breaks.
Systems require all parts to work together in cohesion.
Therefore look at the end-to-end processes and value chains to identify the problem areas. For example, you may like to automate and modernise the Sales department. However, if the Delivery department is incapable of shipping out, Sales will eventually crash and burn too.
Therefore, to strengthen the system, look for end-to-end value streams and ensure that they work seamlessly in cohesion.