Replace side hustles with "parent of toddler age children," or with "second full-time job" is a more realistic measure of commitment, and I'm in the same boat as OP.

The above should be and will be the top comment in this thread, because it's the only advice I can think of that has worked so far.

The benefits of learning to say no generalize to many other areas. Although I like to think of it inversely, as making my "yes"es very hard, and thus every no becomes a reaffirmation of a higher-value yes I had made in the daylight of reflection and conviction.