I can't speak for everybody, but I received a kidney from a living donor in early 2020. I am currently dealing with having a short temper and depression. These things did not start until about the last 6 months, leading me to believe that they are due to pandemic and work related frustrations rather than the transplant itself.
I had several complications immediately after the transplant, (dissection of the artery) but they were able to fix it, and I recovered quite well afterwards.
Please be aware that while some things improve almost immediately, at least in my case I didn't feel like myself until about 9 months after transplant. It's difficult to describe, but I think I expected to be really happy after transplant, and for a long time I was just okay.
I am happy to report that my kidney function is now pretty good, and I'm physically back on top of my game. I am a paramedic / firefighter, and can run circles around some of the younger guys.
While I have some lingering issues with my mood, I spend each day remembering to be grateful for the gift I was given.