Pilot reported taking evasive action entering the traffic pattern to avoid a departing aircraft resulted in an NMAC event.

Narrative

Approaching ZZZ on decent for the left-hand traffic pattern for Runway XX; I had a near miss with a departing and climbing Aircraft Y.Events leading up to encounter:Aircraft Z announced he was on strait-in final for Runway XX; followed by Aircraft A announcing he was doing the same; to follow Aircraft Z. As the time progressed; Aircraft A announced he was on a 2-mile final. After Aircraft Z announced he was clear of the runway; Aircraft Y announced he was departing Runway XX and departing southeast. Aircraft A immediately announced he was making a left 360 deg. turn. I later talked with Aircraft A pilot and he indicated he made the 360 deg. turn to avoid a conflict on the runway and avoid Aircraft Y wake the turbulence. I announced my position; 8 miles east with my intentions for a left pattern to land runway XX. Aircraft Y announced he was departing southeast; which was his last call I heard from that aircraft.Near Miss:As I descended for the pattern; I called 4 miles to the east-southeast descending through 10;300 ft. I noted on my ADS-B display Aircraft Y was continuing his turn toward me. I searched visually for Aircraft Y and now had a visual on the Aircraft A. I observed he was heading directly towards me. Our closure speed was high: I believe my ground speed was on the order of 160 kts. or more; and I speculate Aircraft A ground speed was greater 200 kts. Density altitude was approx. 9;600 ft; so true airspeeds were high.I called I was at his '12 O'clock and diving to miss Aircraft Y' and that 'I was on his nose.' At that same instant; I made a strong push-over I would estimate at -0.5 to -1.0 g's. I did not hear any radio response from or note any maneuvering by Aircraft A. I commented over the radio 'that was a near miss.' The pilot of Aircraft Z commented (now taxing) he was watching on ADS-B and said that it was 'not fun'.I later talked with the pilots of both Aircraft Z and Aircraft A and they indicated that they could see my aircraft on their ADS-B In.Comments and Concerns: ADS-B In alerted me to the impending conflict; with just enough time to take evasive action. Given I was flying an aerobatic aircraft; the negative G's during the evasive action were not stressful on the aircraft or pilot.I do not know how the Aircraft Y is equipped or whether the pilot was distracted during climb out. Based upon the communications; I suspect Aircraft Y pilot departed VFR and was picking up his IFR clearance in the air. If so; it is conceivable that the pilot had switched frequencies to ZZZ Center; even-though he was still in the airport environment. If this is the case; I would suggest departing aircraft continue to monitor the UNICOM frequency on a second radio until well outside of the airport environment.My aircraft is equipped with ADS-B Out on the UAT (Universal Access Transceiver) (978 MHz). Perhaps some aircraft only receive ADS-B form 1090 MHz and not dual band.