
Prerequisite: Proficiency in shortbows and longbows
You have trained extensively in the use of bows, following the old saying that “a warrior trains until they get it right, but a true bowman trains until they never get it wrong.” You gain the following benefits:
- You add twice your proficiency bonus to ranged attack rolls made with a shortbow or longbow, rather than your proficiency bonus.
- Whenever you take the Attack action on your turn and all of the attacks made were with either a shortbow or longbow, you can use your bonus action to make an additional ranged weapon attack with the same longbow or shortbow.

This is absurdly broken with Sharpshooter. It reduces the attack penalty, eventually negating it, and allows an extra attack to get +10 to damage on.
Fair. How would you fix it?
Maybe add 1.5 times your proficiency bonus to attack rolls, although there isn't any existing material to base that off of.
The second attack isn't too broken, so you probably don't need to fix it.
How about, instead of doubling proficiency bonus, you can add a bonus to attack a limited number of times a day, and it can’t stack with sharpshooter.
I’m taking both of your advice.