How to scale up Rapid Shot?

https://pathofexile2.wiki.fextralife.com/Rapid+Shot

So far, I have been very happy crafting my own build to progress through the game. My main strategy has been throwing heated flashbangs at groups and beaming bosses after buffing.

As I fix up my gear to get into maps, the idea of only using rapid shot is very appealing, but I'm not sure how to best scale its damage. Moving around passive points is already quite expensive and the projectile damage nodes I have relied upon are having diminishing returns.

In hopes of sticking with this skill which has been lots of fun, I would appreciate advice on how to boost its damage output to endgame.