My wife manages my time for me. She regulates.
The obvious solution is to do everything at the same time and to connect whatever possible sequential vs parallel execution. If you're go to workout in a gym, so buy things after and in the meantime make your things like readings and call whomever needed. I can't even imagine, but wife says I have to learn.
To to be on average 8 hours and a absolute no work outside worktime policy. My bosses can not reach me in my recreational time. 10 hours is the absolute maximum that i work in rare situations. After nine hours i try to make it easier for the next day me to continue.
You must be in great physical form. You seem to have your priorities well sorted.
My rule of thumb is that we have 100 (24-10)*7 hours a week to manage. I arrived at the 10 hours downtime / day as sleep + grooming + essential eating. It appears that you work for half of those hours. I admire you for allocating time to work out and spending time with family. You don't mention how much time is taken up by commuting. If it is more than 20 minutes then I would suggest audio books, etc as way of being more productive during your commutes.
If I were in your situation, I would try to get an hour each evening to read/learn. Then perhaps two blocks of a couple of hours on weekends to work on your hobby, etc.