Very low URP performance for my mobile 2D game

I added the Universal Render Pipeline to my game to use the Shader Graph to improve the graphics of my game. But I ran into a performance issue. Even without using any PostProcessing effects, the game does not run smoothly. Using a profiler over USB on my Android device, I saw that PostLateUpdate.FinishFrameRendering was taking 13ms of CPU time. FPS changes from 60 to 30 approximately every tick. I need to achieve stable 60fps.

Statistics from the game mode in the editor:

When I change QualitySettings.targetFramerate from 60 to -1, the profiler shows that now most of the CPU time is spent on WaitForTargetFPS (idle CPU as I understand it) and the game runs on 30 FPS. I am assuming the mobile device or URP is conflicting with the targetFramerate parameter.

Profiler screenshot when targetFramerate is 60 and targetFramerate is -1:

I tried to disable almost all objects in the scene and disable PostProcessing on the camera (although there were no PostProcessing effects on the scene), but I did not get a significant performance gain.

About textures in my game: My game is pixel style. My largest texture is 128x96 pixels. On most Texture2D WrapMode is set to Point.

My Unity version is 2021.2.4f1