Do NVIDIA solutions also outperform the Apple M-series in performance per Watt?

No, that's why Apple uses Performance Per Watt not actual performance celling as the metric. In actual workloads where you'd need this power then actual performance is what matters not PPW.

Probably comparable, but that's only with business-grade products, it's why Apple's current silicon is so remarkable on the market at the consumer level.

Thanks.