Adjust the viewport in the Game view after you add a pixel perfect camera to your scene.
Use the Crop Frame property of the Pixel Perfect Camera component to crop the viewport in the Game view. Use this property if the aspect ratio of the Game view makes it wider or taller than the Reference Resolution you set in the Pixel Perfect Camera component.
For more information, refer to Pixel Perfect Camera component reference.
By default, the Filter Mode of a Pixel Perfect Camera component is set to Retro AA, which prevents sprites shimmering when they move, but can make pixels look blurry.
To make pixels sharper but increase shimmering, set the Filter Mode to Point.
By default, Unity renders at the full resolution of the viewport in the Game view. As a result, when you rotate sprites, the sprite pixels rotate at high resolution and create smooth diagonal lines. To keep pixels upright instead, set the Grid Snapping property of the Pixel Perfect Camera component to Upscale Render Texture.