Setup for attaching drywall to metal studs
What you used originally is what it used every day by professionals, handymen and DIYers alike. A drywall gun with fine thread drywall screws. For heavier studs drill-point drywall screws can be used.

If what you did works for you then keep at it. It's just a lot slower than a drywall gun. So if this is just for you and small projects there is nothing wrong with an impact and a sensitive hand.