@hope4clay Hi Clay. I just wanted to touch base with you. We had bilateral tkr just 4 days apart and I too am very obese. My size hasn't prevented my activities in the mornings. These knees are built for all terrain conditions. So while like you I need to seriously loose weight to ensure longevity from them, it need not be a mental blockage for you.
I mentioned my activities in the mornings because my activities in the afternoons include ice, elevation and sleep. I am always shattered in the afternoons to early evenings. My body gives me a window in the am to achieve what I want to or need to and then tells me it's back in charge and to get into bed. So I'm saying that I am mirroring your exhaustion. I also am frustrated with progress so started recording what I'm doing so that I can see change. I can currently only walk 450 metres around my block and it takes nearly 10 minutes! I've decided that's OK, because I'm just going to slowly improve it.
I also forget everything with brain fog.
I make sure I celebrate wins even small ones. For example, I walked the youngest to his class in the mornings without a crutch. Guess what? I need the crutch in the afternoon pick up, but again that's ok. I also managed to fish standing up for an hour. I have fished from a chair for years. I also made a whole meal for my family this week. It was only bolognaise but the only one I've completely finished unaided.
One of my knees is better than the other. My knees are different to yours, your knees are different to others. Our journeys are aligned, but at different speeds and on different vehicles.
Keep smiling, look for that little positive, let your body decide the schedule and find "your window ".