Suggest to follow the Rambo/Hawkeye idea of having arrows with different functions.
One way to implement this is to add “runes” to arrows that can give that stack of arrows addition feature
Ruby runes: additional 5% fire dmg
Onyx runes: additional 5% strike dmg
Emerald runes: additional 5% nature Dmg
And so on.
To craft this rune you would need engineering 150 and jewels + motes