i recommend exercise. I'm over 50, and often after work I'll feel totally drained. after some kind of physical activity - and food - I have energy well into the evening. 20 years ago, I didnt have to do this, but at my current age, this fixes it.
I suppose it was technically possible while working in an office, but such a hassle. Always resulted in losing some workout time around the edges, too.
An hour in the morning and an hour-and-a-half around lunch have made it so much easier to stay sane, and provide nice cover to decline meetings by pointing to a calendar conflict.
Exercise is magical, it gives you superpowers of focus and confidence that you can solve all problems. If everything is going wrong, it's the first place to check - are you exercising? If not, fix that. And maybe everything else goes away.