Strength training for manual transmissions?
 

I'm in a quirky scenario. During pandemic I had medical issues that put me on a drug that caused anorexia and muscle loss, I'm 5' 10" and had dropped to 106 lbs. I'm recovering now, up to 118, but a friend from a trucker family warned me that if I get my class-A and go long-haul my wrists and forearms will be killing me from all the shifting if I'm put in a manual, which I may have no control over. With luck I've got 5 weeks until I get my CDL.

My question is, what specific exercises would strengthen the appropriate muscles and tendons in relation to shifting for 11 hours a day? I've got 5, 15 & 25 lb dumbbells, resistance bands, and a grip strength device.
Would it be grip strength device plus dumbbell forearm curls as heavy as I can go for reps? Maybe the old school pinch grip static holds of the 25 lb dumbbells?

Luckily I ran a lot before that medication, so my legs are still strong-ish for the clutch. It was the last muscle left on me, lol.