C-172 pilot reported a NMAC with another aircraft while in cruise. Pilot took evasive action to avoid a collision.

Narrative

I was navigating under Visual Flight Rules with flight following from ZZZ Approach and was attempting to find an opening to fly around the broken layer between 3;000 and 8;000 feet MSL. My original intended altitude was 4;500ft for westbound navigation but notified ZZZ Approach that I was navigating to maintain VFR. I was notified of a traffic alert while navigating at 5;000 feet and notified ZZZ Approach that I would conduct a 180-degree turn and clear myself of the traffic. I came to the conclusion that attempting to navigate between the broken layer of clouds was not the safest course of action and began to descend to 2;500 to operate below the layer. I began a turn to the North at 4;100 feet while descending to maintain VFR and asked ZZZ Approach if it was safe to turn back westbound to my destination and if the traffic was no longer a factor. I received confirmation that the original traffic was no longer a factor and began my turn to the west while scanning north and west to make sure it was clear. Once I reached a heading of approximately 300 I spotted an aircraft below me traveling westbound that had departed from ZZZ1 (determined after the completion of my flight) directly off the nose of my aircraft and executed an immediate turn to the east to deconflict as the aircraft was crossing. ZZZ approach then inquired if I had two transponders on board my aircraft; to which I responded that I did not; but I had the traffic in sight.I believe that the cause of the incident is due to the current task loads of ATC operators. On this flight; ZZZ Approach did seem to have a higher volume of traffic than previous times I have flown through their airspace. When I inquired if I was clear of the traffic; I believe I should have been made aware of the second aircraft that was in my vicinity. Furthermore; as we were near/in ZZZ1 airspace; ZZZ1 should have alerted the aircraft that had just departed of my location and the possible collision. After reviewing the flight path online of the other aircraft; I do not believe they were made aware of the situation and may not have seen me at all as they did not maneuver.