Ha! A question I can answer from so many different points.
I am a Gujarati - and have known many Parsis, both in Gujarat where I grew up and in US where some of them had lived for generations. I’ve also known several Iranians. And I’ve not seen them to appear all that different from me, or my extended family though we have lived in the same few square miles of Gujarat for at least ten centuries - except for the last seventy odd years.
Parsis are distinct because of the endogamy the same way, broadly speaking, the rest of India practices endogamy within their caste. A further distinction is the food, which has a lot more fish, meat and eggs than a typical Gujarati - who would be vegetarian. But they aren’t all that different from some of the people of the region who do eat fish and eggs with the same fervor.
The Parsis got the ascendancy in the time of British rule, because they were viewed favorably by the British for a variety of reasons. This is not to take away the achievements of the Parsi community in India, it is just to provide the context in which it did happen.
The Zoroastrian religion is related to the proto indo-Iranian faith. And the contrast between the Zoroastrian and Vedic myths is like two sides of the same coin. The language of Avesta is quite intelligible for someone who understands Vedic Sanskrit, and I do. Incidentally I’ve read Avesta in Gujarati script, and it’s available on archive.org.
The right hand is auspicious in Indian religion as well. And it has never been the cause of my questioning it. But then i learned my letters with right hand as well, though I was left handed and started out writing with it.
My reason to question religion was more fundamental. Being born to the family of priests, I was taught vedas and I couldn’t bring myself to believe them to be the only source of knowledge or wisdom - in light of the rest of the education, having learned it.
It was beautiful poetry but then even Shakespeare has written beautiful poetry and people didn’t make a religion out of it.