Understanding the theory of special relativity

Understanding the theory of special relativity.
The amazing thing about our world is that, apart from one person (I'm looking for another name), no one has ever properly understood the theory of relativity, despite the fact that for decades, Dr. Hachel explained things in the simplest possible way.
"If you can't teach the theory of relativity to a seven-year-old, it's because you haven't understood it."
Doctor Richard Hachel.
If you ask a specialist in the theory (be it Einstein, Poincaré, or the bigwigs of today) how the reciprocity of the relativity of chronotropies works, and to correctly explain how one can teach, without cheating, without going off the rails, the Langevin paradox, NOBODY in the universe (except me) knows how to answer. And those who say they can do it are liars or bastards.
Langevin's paradox.
Langevin's paradox is to accept, totally, by a powerful faith, the idea that Stella will travel in the cosmos for 18 years of her own time, with a speed of 0.8c, while on earth, her brother will age 30 years, which is well demonstrated (if we follow what I say) and poses absolutely no problem of truth or coherence. All on a journey, in Terrence's frame of reference that will be made over 24 light years (12 round trips), without time gap (ridiculous idea) without watch jumps, nor anything improbable to understand.
What is true is that, continuously, second after second, in Terrence's frame of reference, the internal mechanism of Stella's watch will beat less quickly. It is said that this one has a lesser internal chronotropy compared to Terrence's watch. And we breathe, we blow. This will happen constantly, second after second, and during the 30 years that Terrence will compare himself with Stella's watch.
But what is also true is that the laws of physics are the same in all frames of reference, and that the effects of physics are reciprocal by permutation of observer. For Stella, and this is where humanity makes an extraordinary block on the theory, it is the opposite that is true. For her, it is the internal mechanism of Terrence's watch that beats constantly less quickly, and this during the 18 years of his journey.
The first physicists, who at the time only knew Einstein and Poincaré, immediately understood the immense paradox. Some have tried to introduce the notion of a U-turn, a change of frame of reference, a jump of watches, etc., showing that no one, until today, has understood the beauty of the theory, its clarity, its genius.
We have just entered the year 2025, and, don't laugh friends, Dr. Hachel is considered an idiot, and those who pretend to explain things with bogus artifices are considered people who have a perfect mastery of their subject.
The same ones who tell us about the Ehrenfest paradox, the Andromeda paradox, the paradox of the train in a hangar, the big bang, general relativity, black holes, spaghetti and white fountains.
All this is stupid enough to cry.
R.H.