>>21836119
That depends entirely on what you mean by "authentic" and "original". Theravada is, aesthetically, the most similar to how the Buddha and his original Sangha of Monks and Nuns lived. There is, of course, an aesthetic to metaphysics, ethics, etc. On the other hand, most of how the laity engage with Theravada is through worship of Bodhisattvas and by performing donations and labor for the monks, and that's pretty clearly not what the Buddha and his pals were up to. Also, orthodox Theravada is INCREDIBLY rigid (except in its mystical aspect, where it's bonkers) and based on recitation and recall of existing, codified, information, and while the earliest Sangha was all about memorization of texts, it still placed a huge emphasis on innovation, meditation, and summarization of texts.
The Mahayana, by contrast, is highly aesthetically divergent, but in terms of the actual content of the religion, it's not actually that divergent. The most striking aspect of the Mahayana is their summarization of the Buddha's words into "discrete sutras", such as the Heart Sutra, the Flower Garland Sutra, etc. This probably came about because of the sheer necessity of moving monks and texts through the areas that the Mahayana developed in (NW India, Afghanistan, and Central Asia), so the whole "monastic slime-mold" thing that Theravada does just could not have been done. The Mahayana also has lots of "dude just shows up and starts meditating" instances, unlike the Theravada. This isn't to say that the Mahayana lacks rigid and hierarchical monastic structures (see: Tibet), but rather that unlike the Theravada it seems to have more room for "haggard guy shows up, meditates, starts dropping wisdom bombs" within the orthodoxy. The Mahayana is also a lot more forgiving of people just going off into the woods and meditating for long periods of time, again, unlike the Theravada, where such "dropping out" is viewed as heinous. This Mahayana allowance for asceticism is, of course, far more in line with the Buddha and his original sangha.
If you're looking to import "which flavor of Memethodoxy is the must TRVE" from Christianity, don't bother, that's not how it works.