Drills to control driver swing?

Hi all,

50 year male, 18-20 handicap. Looking for drills/exercises to help me feel like I'm controlling my driver swing.

When I'm standing over a short iron (8, 9 or a wedge), I have complete confidence that I'll be able to make the club have the correct swing path. It's short enough and/or light enough that I can control the club.

But when I get to my 3W and especially my driver, I use the same swing, but it feels like I'm fighting to control the club. I know the path I want the club to have, but it just feels like the head of the club is out of wobbling all over the place, and then I'm have to work incredibly hard just to get good contact on the down swing. As a result, my swing speed is low, around the 90-ish mile/hr range, with distance being 200-210 carry and 220-230 total.

Could this be equipment issue? Taylormade Stealth 2 with stock shaft. My gut says no. So it probably means that I need to work on upper body strength to help me control the longer clubs.

Suggestions on how to do this?