Just adding some comments: yes, it hurts! Really intense pain for me lasted about 10 days, but several weeks before it subsided. And PT will definitely not be a piece of cake. If possible, get to know your PT person/group that will work with you after the few home visits from whoever gets assigned to you. I had an awesome therapist, whom I had worked with before for shoulder surgeries, so I knew I was in good hands, and we were on the same wavelength regarding how far to push.
The day after the surgery the hospital PT got me walking up and down stairs with the walker, plus doing circuits around the hallways. Sounds crazy, but it was not a big deal. 2 days after surgery I already had a 108 degree bend/flex, but it took me months to get the leg totally straight - the last 2 degrees would not come. No worries, though. Persistence and patience got me through.
Now, almost 5 years after the TKR, I don’t really notice the knee, and to me it was definitely worth it.
Good luck!