> Yes, individual English words don’t map 1:1 to individual Sanskrit words

That is exactly why words of Sanskrit are "non-translatables". Because not all words map 1:1. Please look up the meaning of "non-translatables". Whenever there is no mapping 1:1 that word is called a "non-translatable". It does not mean what you think it means. I'll explain below.

> Rajiv Malhotra would have had to write his book Sanskrit Non-Translatables in Sanskrit, and not in English as he actually did.

"Non-translatables" does not mean the word cannot be translated. It means that there is no equivalent word in English, necessitating one to provide a lot of extra explanations to convey the meaning. For example, let us assume that there was no word called "Sun" in the English Dictionary. Then to translate "Surya" you would have to put extra effort in translating it by saying: "see that spherical ball of light that is emanating a glow and lighting up the sky? It is a Star which looks different from Stars in the night sky due to proximity to our Planet as well as the fact that our Planet is revolving around it. That object is Surya". Now this is a non-translatable as there is no direct 1:1 mapping.

So if the translation of Surya is inaccurate (say the translator describes it as a bulb in your room — which is also a shining ball of light) it ruins the entire translation.

You can read the definition of non-translatable here [1].

[1]: https://www.trustedtranslations.com/blog/non-translatable

As far as the video is concerned, yeah even he gets some of it wrong (like in the example you rightly pointed out about Stuti/Student). But this was the only video I could find that explained in English as I had assumed you are an English speaker (from the West). It sort of explained why some words cannot be translated.

Like one non-translatable is Aatma. Aatma in rudimentary sense is just "Soul". But which "Soul" is this? The Abrahamic definition of Soul? Then that is not what Aatma is in Sanatan Dharma. Heck, even in Sanatan Dharma, there are various interpretations of Aatma based on the school of Vedanta you follow (Advaita, Vishishtadvaita, Tattvavada/Dvaita etc). In Advaita/Monism, Aatma is single entity pervading the entire Creation, both within and outside, and the Creation itself is Maya/Illusion whereby the Aatman = Brahman (God). So in essence, there is no difference between God and you as whatever perceived difference you have is an illusion. In Vishishtadvaita, Aatma is divided into infinitesimal parts with all parts eventually combining to form a whole. The Creation is not an Illusion in Vishishtadvaita. But since ultimately, all Aatmas combine into one Brahman, it becomes Advaita in the end. So it is Vishishtadvaita (Qualified Monism). Then you have Tattvavada/Dvaita which states that Aatmas are separate entities yet completely dependent on the Brahman (God). The size of the Aatmas is defined as 1/1000th of 1/1000th of the thinnest strand of hair on a horse. Jains have a different definition of Aatma: where the size of the Aatma is equal to the size of the body that it occupies. Buddhists do not believe in Aatma's existence at all. So as you can see, each Dharmic school has its own interpretation and explanation for what an Aatma is. But when we discuss about Aatma within the schools, we automatically know what is being talked about: the indestructive, immortal part of what makes a inanimate object animate. Now this is not equal to the definition of Abrahamic soul (from my understanding of Abrahamic texts: that God breathed the life-force/soul into Creatures). In Sanatan Dharma, God does no such thing. The Aatmas are literally immortal with no beginning or end. And depending on the school of thought you follow, the Aatma is just one entity or many or none at all.

So which definition will you use for translation? Invariably, Western Indologists use the rudimentary Abrahamic definition "Soul". It is incomplete. And hence is non-translatable.

It does not mean you cannot translate at all. It just means there is no 1:1 mapping because of lack of vocabulary in the language that you are translating the word into.