Thnx Phizzy!
Hope you enjoy many happy hours with google scholar. The only hassle you're going to find will likely be being able to access many of the academic sources. You need a good library to help you do that. Not sure where you're located, but in Australia many university libraries will let you join, but charge you. e.g. Sydney uni, charges $40 a semester and that's $160 a year. And, (grin) consider getting a portable HD to store all the stuff you then download.
The video you've watched, I suggest you can be quite confident that any ideas presented are partly tradition and partly time-modified belief. No religion will be unchanged over time. Early Christians would be lost in both a Catholic Cathedral and a Kingdom Hall, and contemporary Zoroastrians will believe things that are different from ancient beliefs. As the saying goes, Change is Constant.
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I was checking out images of 'fire temples' this morning and my search threw up this Pinterest page:
https://www.pinterest.com.au/mazdayasna/fire-temples/
There could be more, but since Pinterest disfellowshipped* me, (haha) I get a few roadblocks in looking for stuff on that site.
Also there was this longish article ( I havn't checked out the web-site) titled- Is there a network of sacred fires across the Himalayas and Central Asia? From Baku to Nepal and back.
Link: http://www.austriaca.at/0xc1aa5576%200x00358452.pdf
Maybe Zoroastrian influence is greater than imagined.
But, most intriguing to me (it set me off to investigate the changing religious beliefs of the ancient Sogdians, who at one stage were the major traders on the ancient East-West Trade Network, now called the Silk Road).
From a web-site called Quartz India, " The forgotten history of how ancient Zoroastrians helped create the old Silk Road." Link: https://qz.com/india/987379/the-forgotten-history-of-how-ancient-zoroastrians-helped-create-the-old-silk-route/
The Sogdians even attempted to take China over (during the Tang Dynasty) and so weakened that dynasty that it eventually collapsed leading to 50 years of chaos (known as the Five Dynasties and Ten Kingdoms era) until a new strong central authority (the Song Dynasty) established itself.
To understand their full influence in China, check out this article from the (USA) Smithsonian-Freer/Sackler group, "The Sogdians- Influencers on the Silk Road." Link: https://sogdians.si.edu/the-sogdians-abroad/