My kids only volunteered a tiny amount (and no volunteering was required by their boarding schools, although there were some opportunities).
One volunteered at a food bank, another at a nearby zoo and at a school for kids with intellectual disabilities, and the third coached local kids. But nothing really stuck, and none of those activities really influenced my kids. They were not working with others their age from diverse economic backgrounds, which is one of the benefits from national service.
If I could wave a wand, kids doing national service would NOT live at home but would be sent to other areas of the country.
On the other hand, I volunteer a TON!