I've been feeling a bit under the weather so I haven't had the energy to tackle hard topics.
For these kind of days, I always like watching videos on YouTube or Twitch, or listen to podcasts. You can learn new concepts but it's not too complicated.
I've discovered The Coding Train on YouTube. I like how Daniel Schiffman works through problems. You can learn a lot by following his thought process. It's sometimes a bit chaotic but fun to watch.