unity – Saving .png from render texture leads to a lot darker picture

So I managed to get it working because of recommendation from DMGregory. Since sRGB is a readonly area, you need to create a rendertexture in code. Right here is my full code:

[SerializeField]
RenderTexture rt;

[SerializeField]
Digital camera cam;

[SerializeField]
string fileName;

[Button("Save png")]
public void SavePNG()
{
    RenderTexture mRt = new RenderTexture(rt.width, rt.top, rt.depth, RenderTextureFormat.ARGB32, RenderTextureReadWrite.sRGB);
    mRt.antiAliasing = rt.antiAliasing;

    var tex = new Texture2D(mRt.width, mRt.top, TextureFormat.ARGB32, false);
    cam.targetTexture = mRt;
    cam.Render();
    RenderTexture.energetic = mRt;

    tex.ReadPixels(new Rect(0, 0, mRt.width, mRt.top), 0, 0);
    tex.Apply();

    var path = "Belongings/Textures/Rendered textures/" + fileName + ".png";
    File.WriteAllBytes(path, tex.EncodeToPNG());
    Debug.Log("Saved file to: " + path);

    DestroyImmediate(tex);

    cam.targetTexture = rt;
    cam.Render();
    RenderTexture.energetic = rt;

    DestroyImmediate(mRt);
}