I had exactly six months between my two TKRs. After the first one I had no PT except for the three days in hospital, then I was sent home with a little booklet telling me what exercises to do. Because I was a bit of a wimp, I suppose, and the exercising hurt, I don't think I did anything like as much exercising as was recommended, and certainly nothing at all like the amount you have done. You will therefore probably be at the same stage after ten weeks that I was at after 25 weeks!
I was a bit concerned that my left (first TKR) knee wouldn't be up to coping with walking, standing etc when my right knee was replaced, three weeks ago today. However, it has been much much easier than I thought. Both legs are now really strong, and I am walking well without aids. I think the exercises I am now being much better about doing are helping both knees, so the left one is improving too.
I still don't have any PT othen than what I do myself at home. I do have an exercise bike, which I've managed to get round in a full circle for the first time today.
You sound as if you are a young, otherwise fit football player, whereas I am a 66 year old granny who wrecked her knees playing badminton 30-odd years ago. If I can find huge improvements in doing pretty minimum exercise post-op, then I would think you have nothing to worry about.
I would say that after the first week post-second-op, the first knee seemed stiffer than it had been for some time, and I am sure this was due to the fact that I did virtually no walking for the first week. I usually walk everywhere, usually at least a mile every day. So, I think you are right in thinking that the forced lack of exercise to start with might affect your first knee - but it's a very temporary blip. As soon as you get going again your first knee will take off from where it had got to.
Best of luck for op number 2. It was much easier second time round for me, so hopefully you will have the same experience!