C152 pilot reported engine issues during takeoff that eventually resulted in a diversion to the nearest airport.

Narrative

Departing from ZZZ; I wanted to go to ZZZ1 and ZZZ2 to practice landing (fullstop taxibacks) but i saw that the weather was not good in north side of ZZZ3. I brought Person A with me after his flight lesson we live in the same accommodation. I told him that i choose not to go on the north side due to the weather and we will go to FBO instead to practice the same exercise that I was supposed to do at ZZZ1 and ZZZ2. The weather at ZZZ was good. (Info 1 wind 140°6kt visibility +10 SKC alt 30.02) I followed all the check list until the takeoff everything was perfect the magnetos was perfect (1700 RPM slight drop for each magneto not more that 125 RPM loss and not more than 50 RPM difference between them). We took off Runway XXR I noticed that after the takeoff there was a slight drop in RPM 2300 instead of full power but we were still climbing and I could keep my speed too (between 65 and 75 for climb) When I took the heading to ZZZ4 and when I levelled the wing everything went back to normal the power went back to full. So as normal when you are wing leveled you put 2400 RPM for cruise. The cruise was normal every parameters were perfect (oil temp/ pressure; alternator; charge; breakers) so I decided to continue the flight. I landed Runway XY vacated via Taxiway 1. An aircraft was doing touch and goes so I hold short XY. Then line up and wait behind him and I waited for him to begin his crosswind to takeoff. When taking off I noticed that we took more Runway that usual. After that. The RPM went to 2300 RPM even when I put full power. The speed started to decrease so I pushed on the yoke to keep it but the vertical speed starter to decrease. I had two choices: either I pull up to keep the vertical speed (risk of stalling) or either I keep my speed (high rate of descent). So I [Requested priority handling] due to loss of power and requested all the aircraft in the vicinity of the Runway XX-XY to exit the pattern to let me land on Runway XY. After the landing I went to park (I went to a wrong spot) so 45 min after my landing a Lady came to check if I need help because she didn't know why we were staying near the aircraft without doing anything ( we were actually waiting for the school to call after our initial call with them) so she brought someone to tow the aircraft to the good spot.