For example, perhaps you play games and want to make a tool/website that makes some aspect of your game-playing life easier or more enjoyable.
You can then use that project as an opportunity to learn new skills and put them to use when building out functionality. Having something you're actively looking forward to doing is an easy way to have that energy boost even after an exhausting day at work.
Alternately, don't even try to put pressure on yourself to do anything like that during the week and perhaps just allocate a couple of hours each evening on the weekend to learning when you've had time to do other fun or less exhausting things throughout the day.
I can sacrifice a couple of hours after 10pm when my kid sleeps but I feels exhausted doing that for a few weeks. I'm trying to get up early, maybe around 5am so I can enjoy 2 hours of free time between 5:20 and 7:20, when I need to get my kid and wife out of bed. The ultimate plan is to move up to 4:30am so I have an extra 30 mins to make breakfast, exercise and shower.
It's tough. Good luck. If you don't have a kid, you should aim for 4 hours at least. Build up slowly. Manage your workload so you don't feel exhausted after work. 2 hours in the morning + 2 hours in the night are reasonable.