I personally find that my desire to hike is as strong as ever, although the Covid-19 problem has knocked me sideways. I'm very lucky that I do not have any muscular, arthritic, or any other problems or issues at the moment. Mind you I do wake up most mornings and think is this the day when I'll get my comeuppance? It hasn't happened yet but I'm sure it will, but I just don't know when. I only have one small problem which I just 'walkthrough,' after a day or two my toes 'burn,' its a most unusual pain but after 24-48 hours it just goes away! Over the years I've also had a few days when I just put up my tent, get in, and just 'sleep off mood' but in the mornings I've always managed to bounce back. Mornings have always been the best time for, the evenings can be but not always.
When I've hiked the first couple of days for me are always the worst, it really takes me a while to get into a rhythm. I also never feel at my best at the start of a hike and if I'm going to feel miserable and under-motivated it will be in the first 2 or 3 days.
I've learned to live with it, I recognize that no matter what it's going to happen anyway, and nowadays having this personal knowledge is also what helps me to get through it. I'm also one of those who prefer longer walks (7 days or more) rather than short ones and I'm not a keen day walker either. That's one of the reasons why I run each day.
My greatest problem when hiking is usually after a week, personal loneliness moods can set in, one of the reasons why pubs are important to me, I like to go in one each day and make the effort to talk to people. My worst memory was walking in the Pyrenees and not seeing one human being for 4 days! That was really depressing.