The reliability of the written Torah and its place in Judaism

Hello Rabbi,
I have two questions that I would appreciate if you could answer or direct me to places that address the subject.

1. Even if we assume that some of the written Torah was given to Moses at Mount Sinai, I still think it is quite absurd to say that it was preserved and that the Torah we have today is identical to the Torah given to Moses at Mount Sinai. If so, what obliges us to this particular text (both at the level of the general stories presented there and at the level of specific words and letters on which the Sages rely heavily in their halakhic rulings)?
2. Continuing with the previous question – even if we say that the Torah has been perfectly preserved and that the text we have is completely identical to the one given at Mount Sinai, once it was given in writing (and not, for example, imprinted within us) it is subject to personal interpretation. At the end of the day, we do not observe the written Torah at all, but only the oral Torah. Even the way in which the Torah should be studied was determined by humans. The attitude towards the Torah became like the attitude towards a literary work – as material in the hands of the creator, which sages can analyze however they please and derive from it what suits them. As a spring, a springboard from which one can jump wherever they want. And of course this is what will happen, because once it was given in writing, we must interpret it in a human way. If so, Judaism and Halacha are completely human and completely disconnected from divinity (unless you say that the entire oral Torah was also given at Mount Sinai, but in my humble opinion, this is quite far-fetched). So what is the point of them, really? What is the point of everything we do if everything is human like any other system of laws? It can be said that Judaism is unique in that its system of laws does not come only to regulate relationships between humans, but also includes commandments between humans and the place. If so, the question remains: what is the difference between the system of laws of Judaism and the systems of laws of other religions (which also contain these criteria)?

Thank you very much!