Why graphics quality of mobile ports is low ?

Hi

Maybe I'm wrong . I made two pixel art scene in Fusion and Unity as HD . In Fusion I can't see full details of pixels and colors haven't good quality on Android It seems graphics have a little blur. After that I made same scene in Unity with same resolution (1280x720) and result was high quality with great contrast and brightness .Also I can see full pixel details in Unity too.

Does Unity make best render instead Fusion for mobile ports ?
If it's yes . Is anyway for improve it in Fusion?

Of course you have to see careful to graphics and maybe in first look seems equal for them.

Thanks
Mehrdad

Jeff
I use 'fit inside and adjust window size' for compile . Also I use other options and result was same.

Retrobolt
It occur for non pixel art is too . Colors in Fusion is opaque instead Unity. You can test and see it easily.

No I don't use it . Please test it yourself with Unity free and get mobile port for compare. A background with a simple character will be 8mb maximum .