“The Star of David contains one downward-pointing and one upward-pointing main triangles, which cross and interpenetrate to form 6 smaller triangles, and a central hexagon. As you can see, the Star of David is considerably less complex than the Sri Yantra.”
Your remark about the Sri Yantra and the Star of David and their differences are quite acceptable according to what has been written on it in older or traditional literature.
What is not the same with me, compared to many others who are interested in these type of symbolic configurations, is that I do not and never have used mantras, yantras, mandalas, pujas, etc. as aids in meditation or such, to bring about deeper insights or more elevated states of consciousness. In my case, insights and realizations came in a different manner, quite spontaneous and simultaneously accompanied by a wide range of mystical visionary symbols, symbols that were initially rather unfamiliar to me. Not totally new, I never had my head in the sand and have always been well informed in medieval and oriental art and culture, but my interest was still rather of the anecdotal kind. I saw many of these things just a wee bit better than cultural oddities. Sorry to say it that way, but honesty requires that. That is how I grew up in still colonial Holland. Maybe I was a bit more open than most but still had quite a narrow span of acceptance, understanding and sympathy.
In my case, and I know this is me 'personally' (I hope you do not see this as criticism on where you are coming from) in my case the experiences were different from most people and rather direct. I do not need to go into that much detail here because I have written about it quite a bit elsewhere on this site. The uncanny visionary experiences with the Sri Yantra and the Star of David was that they were not just a 'bit comparable' but exactly the same.
This is not a matter of argument for me, it is a matter of self evidence. When you see two identical cars, (say two of those new yellow VW Beetles), and you tell somebody about how they are both exactly the same, nobody will argue you. Well maybe they'll say, that they are not one and the same vehicle, but that is clear, there are really two cars, in two different locations that came off the assembly line at a different time but otherwise they are identical.
With my Sri Yantra / Star of David experience it was actually better than that, the experiences were and are exactly the same and identical in all aspects...except... that language wise I heard two different sets of words (one with a Hindu and the other with a Judaic meaning) on two different occasions. Funny though it was in Dutch and Sanskrit not in English. (Odd but then why not.) The multidimensional, complex triangular geometric characteristics were identical, as well as the scintillating colours and vibrating sounds. And why not, the experiences did not bring the limiting factors of time and space with them. Such can be the case with archetype kind of things. (I'm not saying that I would agree that these symbols are archetypes in the same vein as Carl Jung would hypothesise, but that is not the point.)
I do not come from either a Hebrew, Judaic or Hindu tradition, Roman Catholic, yes. But I studied the traditional symbolism quite well after these visionary epiphanies (which also included the tree of Jesse, Adam in Eden, as well as Brahman, Shiva and Vishnu appearances, in addition to that parallels to Hildegard von Bingen's and Theresa of Avila's visions.)
I had to really get into the study of these topics and personalities, as I felt initially, that I had to reconcile my personal views with tradition, to fall in line so to say. However I decided, and this was after some strong visionary instigation by a higher being, that I should let my experiences stand as authentic and identical to the experiences that prompted the tradition of the Sri Yantra in Hinduism and the Star of David in Hebrew, etc. I was urged to conclude that the oriental mystics of yore and myself had identical realizations. The only difference was the matter of depiction, either in oral from, written word, in line art, painting or in sculpture. And as we know all that is time and culture bound.
The ancient mystics talked, painted, sculpted and wrote in their and for their own culture according to their own world view and paradigms, which to be honest is in some aspects superior to ours. So there is nothing wrong there.
There is a difference though in the handling of the multidimensional. More than two dimensions were not widely accepted, perspective was not invented yet. People were more (and I do not mean that in a pejorative sense) psychological flatlanders on a two dimensional earth trying to deal with a separate set of not well thought-out heavenly dimensional beings who were trying contact the lower dimensional ones.
The visionary mystics (ancient scientists really) urged by their insights, discoveries and experiences tried to introduce a complexes story about the universe and a worldview in multiple dimensions to the general population. (We do the same with magazines like 'Discovery')The symbolism of the Star of David, Paradise trees growing up into the heavens, Pyramidal structures, a tower of Babel, mandalas and yantras were supposed to do the job. (There is of course way more to these symbols, but this is not the place to go into that)
When it came to the depiction of such on flat surfaces they got more or less stumped... but they attempted anyway... from that we get the swastikas (the cube), the triple type of yin yangs (3 axes) and the flat mandalas (6 directions, east, west, south, north, up and down) (Ever seen the 3 D sculpted and painted mandala from the ZONKAR CHOEDE Tibetan monastery, 4x4x6 feet, I saw the same theme of that mandala in three visionary dreams, am still working them out).
The ability in those days to depict the multidimensional was limited, but I am sure that their experience and what they tried to convey was the same.... Nowadays we can use the creativity of people like Dan Winters with their computer animation skills to show more and better what is meant and seen by the scientific and metaphysical visionaries supported now by scientific discoveries... that also support ancient knowledge.
There was another experience that came with Sri Yantra / Star of David. This experience not visionary but 'gustatory': the taste of ambrosia, honey, nectar...