This piece resonated with me a lot, as I've also gone through burnout twice - once towards the end of my PhD, and once at a previous job. As a result, I completely agree with your conclusion on getting overwhelmed after once being rather driven and hungry for personal growth.

> Few friends have suggested that I don’t need to have voraciousness for happiness, but the thought of it makes me really uncomfortable

It makes me very uncomfortable too, because in the periods of my life where I lost voraciousness, I wasn't happy in the slightest.