@mercuryrose I have had two TKRs and the first one had minor pain after a lot of exercise but virtually no pain in the second one. Then the pandemic came. I went from walking on a treadmill or track at my health club to having to walk on pavement. That really affected both of my knees. I have given up walking on pavement, I do videos where I am basically walking in place, and the pain is resolving.

I used to do a lot of pool jogging and that felt good, never any discomfort afterward, so I suspect swimming would be similar.

My best advice to you would be to make sure you have the absolute best doctor you can find for your knee replacement. For my second one I went to a doctor who used a custom-made knee (Conformis) and it really did make a difference, plus he is extremely highly regarded.
JK