Yes, gardens are one answer, and likely the best one currently for non-webapps. Distro package mangers themselves are the original gardens. They get a pass because having good incentives have kept them decently honest, but that's fundamentally what they are.

Gardens allow you to make a small number of trust decisions, and then trust all the software they have vetted by extension.

Note that I'm leaving out "walled" because multiple software sources can coexist. "Walled" only comes about when some company tries to constrain you to their singular source.