I asked the same question a couple months ago HERE.
Some good feedback from members in this forum… I am sure they can pipe in again.
I empathize with you and wish you the best. Bass aside- do what the doctors and physical therapist tell you. This is (was) my second surgery on the R-side, I had both done about 20 years ago. I cam through the most recent one OK. Not much pain during recovery, I kept up with the “pain management” by keeping ahead of it before the chance of any onset. I am in a fortunate position of being able to take off for a month from work. I had no pressure and could really recouperate as well as relax… it was a vacation of sorts.
Member @Wombat-metal recommended the D’Addario VariGrip. I bought it and also got a a Fiddilink thingy… both of these really kept somewhat of a finger focus.
You state procedure on the left shoulder… are you a righty bass player? If so, the exercise tools will help your plucking hand dexterity. I am now using those devices for both hands now.
Wishing you the best on the procedure and recovery!
Just guessing from your username handle… you must be a skier having had that procedure done previously… and you are a skier down the hill from me in Denvertown???