Powerful draw

Ability Score Increase. Increase your Strength or Dexterity score by 1, to a maximum of 20.

When making an attack with a range weapon, use your choice of your Strength or Dexterity modifier for the attack and damage rolls. You must use the same modifier for both rolls.

To determine the heavy score for the weapon, you add your Strength instead of Dexterity for Ranged weapons (score 13 base)

You learn how to make a bow more powerful by adding to its draw strength
The extra draw strength you can add can be up to your full Proficiency Bonus (minimum 0)
and adds +1 damage per draw strength added

the added draw strength also increases the necessary score needed to avoid disadvantages for using the heavier weapon