All lineages begin in Samantabhadra, but the Sambhogakāya who communicates this is called Vajradhara, Vajrasattva, etc. Sometimes you see texts in Dzogchen where Samantabhadra is directly teaching Vajradhara.
Are these texts to be taken literally? What you've just said here really put me in mind of Sophia and gnosticism, like the chain of superior wisdom beings descend into matter to "wake us up" to enlightenment. It gets confusing to add another layer to this that everything is an emanation of mind and our buddha nature is identical to Samantabhadra and that everything is perfect but we perceive it incorrectly. This in turn reminds me of this quote from Dilgo Khyentse Rinpoche:
"Everything is perfect just as it is, completely pure and undefiled. All
phenomena naturally appear in their uniquely correct modes and
situations, forming ever-changing patterns full of meaning and
significance, like participants in a great dance. Everything is a
symbol, yet there is no difference between the symbol and the truth
symbolized. With no effort of practice whatsoever, liberation,
enlightenment, and buddhahood are already fully developed and perfected.
This is natural perfection."— from Dzogchen Practice In Everyday Life
It starts to seem that the creative source expresses its knowledge through the manifestation of all things, which are symbols, the necessary components of logical thought. Even if samsara is a result of misperception, I suppose this is possibly sensible. After all, I entertain all sorts of thoughts for my own amusement and then get lost in them.
I don't know if a thorough understanding of reality is necessary to being a good student or even possible, but sometimes when I'm walking down the street trying to imagine myself in the center of the mandala, as other beings jostle me around and I try to imagine them as dakinis teaching me, I do wonder how exactly I'm supposed to be viewing reality. All is a manifestation of mind and nondual, like a big dream, so who's dreaming, these dakinis bumping into me or me?
Sorry for the derail, just some thoughts that didn't seem worthy of starting a new thread (I don't expect to have a long discussion about this, but am interested in whatever you might think about it). Generally, when I start to think/wonder like this, I just give up and do some practice. I feel like there's some sutra where the Buddha said even he doesn't know all the workings of karma because it's so complex and spans aeons and aeons of time, so that helps reassure me that knowing the answer to all and everything isn't really necessary as long as you know enough to practice.
I was surprised once when I asked Lama Tsering Everest some question along these lines and she paused thoughtfully and then said, "I don't know. I'm still learning." in a somewhat mysterious manner. I wish I could explain the enigmatic expression on her face when she said that. I also wish I could remember the exact question I asked her.