An important problem doesn’t have to be difficult. The reason to do difficult things early in the morning is because that’s when you have the most energy. I think you should still do something manageable. I also think waking up and being excited to do something is a good state to be in, so I think how much you enjoy the problem also matters.
You can break up difficult problems into smaller easier problems. It can involve indirection. Doing similar but easier math exercises is an example of indirection, it’s not a lot of indirection, but you are starting another exercise instead of directly working on the same exercise.
What is your “perspective of things”?
Perhaps you only think of difficult things as problems. You solve many problems every day, like answering to posts on the forum. Perhaps recognizing more things as problems and recognizing that you solve them easily would help.