Does your vet do home visits? Maybe it isn't the vet so much as it is the strange smells at the vets. I've taken a lot of cats to the vet and have not had that reaction unless it's from a feral.
One vet I used to go to would take the top off the carrier and work with the cat still in the carrier rather than drag it out of the carrier and immediately set it on edge. It worked for the cats that were less than happy to be there. Most of mine when I take them huddle against me where they are happy and the vet does what needs doing. There are calming meds but I wouldn't use them unless absolutely necessary.
The incision from the spay should be healed enough that a little licking won't hurt. It may even help with the itchiness kitty will be feeling. It's normal.
Assumptions do nothing but make an ass out of u and me.
We can stick our heads in the sand for only so long before it starts choking us. Face it folks. The pet population is bad ALL OVER THE WORLD!