Heruka wrote:dzogchen in its purest form is beyond buddhist concepts, yet buddhism in its purest form is dzogchen.
There are two kinds of dharma: dharma of text and dharma of realization.
There are two kinds of buddhism: buddhism of text and buddhism of realization.
There are two kinds of dzogchen: dzogchen of texts and dzogchen of realization.
In order to establish that "dzogchen" is "without buddhism"; one would have to identify something in Buddhism that Dzogchen is missing; or conversely, something in Dzogchen that Buddhism is missing.
In reality, Dzogchen is just another way of explaining śūnyatāprābhāsvarāsaṁbhedaḥ in relation to the trikāya. No matter how profound Dzogchen may be (and it is the most profound teaching of Buddhism), it does not go beyond explaining how to realize the trikāya state through knowledge (vidyā,) of one's own basis (sthāna):
emptiness (śūnyatā, stong pa nyid; svarūpa, ngo bo; visuddha, ka dag; dharmakāya)
luminosity ('od gsal, prābhāsvarā; prakriti,rang bzhin) nirabhogana, lhun grub; sambhogakāya)
inseparability (āsaṁbhedaḥ, dbyer med; karuna, thugs rje; nirmanakāya)
Since śūnyatāprābhāsvarāsaṁbhedaḥ is nothing more than what the Buddha taught, even Dzogchen cannot go beyond being a teaching of a Buddha.