Scale full screen phaser 3

Phaser 3
1

I am really trying to understand my issue in all my power, but still no luck.

I have a game config such as:

var config = {
            type: Phaser.WEBGL,
            scale: {
                mode: Phaser.Scale.FIT,
                autoCenter: Phaser.Scale.CENTER_BOTH,
                parent: parentDiv,
                width: 1920,
                height: 1080
            },

            width:1920,
            height:1080,
            
            parent: parentDiv,
        };

Now, what happens is , the game runs , but there’re black or sometimes white borders left/right side or top/bottom side. Looks like this is normal since it’s trying to scale it and that’s the best thing it can do.

I am wondering, is it even possible to show my game on full screen without any black/white borders at all and still have it scaled? any best practice or solution?

Thank you in advance.