Proper way to scale assets for the whole game?

[Poe]

I feel like I might be missing something, but so far the only way I have found is by using zoom in the game config. However I am struggling to figure out how the zoom affects other aspects of the game.

I made this function 

    adjustCamera() {
        if(this.floor.width*this.sys.game.config.zoom > window.innerWidth || this.floor.height*this.sys.game.config.zoom > window.innerHeight) { 
            this.cameras.main.startFollow(this.player) 
            console.log('Following Player')
        } else { 
            this.cameras.main.centerOn((this.floor.width/2)*this.sys.game.config.zoom, (this.floor.height/2)*this.sys.game.config.zoom) 
            this.cameras.main.setBounds(this.floor.x, this.floor.y, (this.floor.width/this.sys.game.config.zoom)*2, (this.floor.height/this.sys.game.config.zoom)*2)
            console.log('Centered on map.)
        } 
    }

But camera doesn't seem to follow my player, so I might just be approaching this incorrectly (Maybe I just need to scale each asset individually?).. pretty new to game dev and phaser so please forgive me! 

Any help would be appreciated!