What exhausts you today can become warm-up later.

What is at the edge of your ability now will, with enough repetition, become the easy part of something harder. This happens so gradually that people rarely notice it, and they keep describing themselves in terms set years earlier. The thing you currently dread is a likely candidate for the thing you will one day do without thinking.

When something exhausts you, notice it rather than judging yourself for finding it hard. Then keep meeting it in manageable doses. The change is not usually visible week to week and is very obvious across a year.