If your tumor is not large, the mild cognitive issues will not be an issue after a few months. Recovery from surgery and anesthesia will require a few weeks of good rest. You will notice a big improvement in cogntion after that. Most of the problems we experience after a surgery is integration of the sensory, balance, movement, and spatial knowledge that we have about our own bodies. If you are facing SSD then you should look into the best hearing aid option.
Actually my thinking and problem solving processes were okay post op, but I needed a little more time and quieter spaces to do my thinking in than I had pre op. I use a lot of graphics, handle textiles, and work in the visual arts now at 16 months post op and just as well as I worked pre op. One third of my day is spent at a keyboard and monitor screen. I want to stress the importance and value a bone conduction hearing aid will have for you, especially in a work place.