I too would feel miserable. My bilateral was a week after yours, and my ROM has always been good. I am now an inch away from being able to sit on my heels, but realise now that I am unlikely to ever achieve that. I would be devastated to be in your position.
It seems to me that you are still swelling up. You did a lot of standing in the earlier days, much more than I could have done, maybe your lymphatic system has kind of got used to filling up. I was never able to stand still, had to keep walking around. It is only recently that I can stand for hours without walking around a lot, did four hours a few weeks ago and my knees stiffened up with swelling, but I’m ok if I keep moving around all day now, with short rests. My ROM gets worse as the day progresses, so I know I am still swelling.
If there is nothing wrong with the mechanics of your knees, and your OS doesn’t feel that you have adhesions, then maybe even more patience is required. Perhaps one of the mods will be kind enough to post the ROM progress of one of those people who took nigh on two years to stop swelling. It may give you a bit of comfort.
The only advice I can offer is to not to stand still, either keep walking around or elevate for a while and see if that helps. Difficult to get the chores done, I know, as there is not much to achieve whilst on the hoof.
I sincerely hope that this will end one day for you.