The designer at my firm is adamant about adding custom shadows to some of the sprites in our games.

Above is an example of the required effect; the shadow separator and the shadow below the balloon sprite.

Using the method of adding a similar object with a different tint and lower alpha gives 'no where near the similar result' as the alpha in the required shadows is not uniform across the shadow.

let shadow = this.add.sprite(posX, posY+20, 'balloon')
.setOrigin(0.5);
shadow.tint = 0x000000;
shadow.alpha = 0.3;

let balloon = this.add.sprite(posX, posY, 'balloon')
.setOrigin(0.5);

As seen in this question

Any help getting me a somewhat similar shadow effect would be much appreciated, because I'm not sure how I can achieve this without simply putting the whole shadow as an image.

PS: I'm using phaser 3