I gave up zero dogs because of the constant key punching. Finger cramping after a while.
I've seen several statements about this in different threads.
I developed very intense pain in three fingers on my right hand (mouse hand), and two on my left hand (WSAD fingers) after decades of playing.
At the Rite-Aid pharmacies, you can purchase small plastic bags that are full of little elastic fabric sleeves that you can pull over the fingers that hurt. I've been wearing them for years (every hour I game), and it has lessened the pain tremendously, to the point where I can play all day without pain now. There are different sizes in the envelope, I use the one that gives me the most elasticity/counter-pull. It feels strange playing with them on your fingers, at first, but eventually you won't notice them.
I think it's because the elastic fabric provides a counter-pull against you having your fingers in one position all the time.
If pharmacies in your area don't have them, try Googling Rite-Aid so you can purchase them on-line.