Ask what separates the Vedas from Tantra and most answers reach for caricature: the Vedas are pure and orthodox, Tantra is dark and transgressive.
Strip away the sensationalism and a clean difference remains. The Vedic stream, especially in its contemplative Upanishadic form, tends toward the internal and the transcendent.
To keep it grounded, three places the difference actually shows up: 1. Theory versus practice.
Here is the reading I have come to trust. The Vedas provide the foundational philosophical framework—the what and the why of liberation.
Are the Vedas and Tantra opposed traditions or two halves of one path? The real difference between Vedic and Tantric approaches, and why they complete rather than contradict.