Pilot reported an NMAC with another aircraft in the traffic pattern on approach to VVS non-towered airport.

Narrative

I approached VVS from the southwest and announced my position about 10 miles out. Just before my first position report I heard another pilot of Aircraft Y announce that they were in the area and were using Runway 5. When I began to setup to enter the downwind for Runway 5 I made visual contact with the Aircraft Y and made my way behind them as #2 to land. Near the end of my turn to downwind I saw Aircraft Z about 500 ft. below also appearing to make their way into the downwind for Runway 5 but I did not hear any position reports from them. I kept my eyes on both the Aircraft Y and Aircraft Z while continuing my downwind for Runway 5. Aircraft Z appeared to me to be making their way to the southwest away from the airport and I lost sight of them under the nose of my aircraft. Since I didn't hear position reports from them and they appeared to be moving away from the airport I decided to continue my downwind following Aircraft Y. Aircraft Y turned final and I turned base.After turning base I noticed Aircraft Z again below and behind me who unbeknownst to me was still in the pattern and must have turned base about the same time that I did. I then heard them on the radio question me about whether or not I had heard their radio call about turning base to which I replied that this was their first transmission that I had heard. The miscommunication as well as the low wing/high wing visibility problem contributed to the lack of proper separation of aircraft during landing operations. I could have also made a 360 turn behind Aircraft Z upon my initial sighting of them to give myself more room to determine what they were doing. Also contributing to the incident is that 122.8 is overcrowded in this area with multiple airports commonly having pilots report on the same frequency resulting in congestion of the frequency and contributing to why I may not have heard Aircraft Z pilot or thought that his transmissions were for another airport.