I have problem with png export from Blender. In my rendered mode everything is looking great, but when I click to render this png the quality is bad and my glass structure look nothing like in render mode.
Camera setting full hd
https://drive.google.com/drive/folders/180bRMCFdUu-NTplt8H9l8nJKmy4ulrBn?usp=drive_link
In your scene you have disabled the Scene World in Rendered view, i.e. what you see in the viewport is just rendered with one of Blender's internal preview HDRIs:
About the quality I cannot say anything since your file comes without the HDRI packed into it, which means I only get a purple background color. But from your settings I do not necessarily expect the quality to be bad - maybe you have to elaborate what you mean by bad quality.
If you mean that it is just not the correct environment lighting, well that's not surprising since you are first of all not previewing with the original world background as I mentioned above and when you finally render the image with F12 or Render > Render Image, it uses the world shader which you have set up, not the preview HDRI. And there you have a second problem: you have setup two World Output backgrounds in the shader, a new one with the "forest.exr" environment, but you did not replace the default grey background with it. So it uses the grey background for rendering instead of the EXR image. Delete the old background nodes:
