Not quite. They can be trivial. They can be meaingless. They are synonyms.
Trivial Synonyms, Trivial Antonyms | Thesaurus.com
You would be better off going to a dictionary to understand a word than a thesaurus, a thesaurus will give you a list of words that can be interchanged in some contexts.
Synonyms: atomic, beside the point, commonplace, diminutive, evanescent, everyday, flimsy, frivolous, immaterial, inappreciable, incidental, inconsequential, inconsiderable, insignificant, irrelevant, little, meager, mean, meaningless, microscopic, minor, minute, momentary, negligible, nonessential, nugatory, of no account, paltry, petty, piddling, puny, scanty, skin-deep, slight, small, superficial, trifling, trite, unimportant, valueless, vanishing, worthless
Is an atomic bomb a flimsy bomb? Is it beside the point? Is an atomic bomb or an atomic radius meaningless? A thesaurus will give you a list of words whose meanings can overlap in some contexts. It does not tell you the meaning of trivial when used to describe tautology.
I quoted a textbook that does this to, so it's not just me rephrasing if it but it helps to reduce my evidence to just me, that's fine
But that's what it means, anyway.
Unfortunately, you are quoting a textbook that disagrees with you. I suggest you read it again

The text book isn't saying that survival of the fittest is a tautology, it agrees that the Harper magazine description is a tautology, but that survival of the fittest goes beyond the tautology described in the magazine. The text book point out that there are about independent criteria for fitness, beyond merely those that survive. Of course you have tried to handwave them away, calling them 'just so stories'. But that is a different argument. Because there is a separate meaning to the term fitness, whether just so stories or not, survival of the fittest cannot bea a tautology.
You hadn't demonstrated that.
It is a simple statement of fact from an eye witness.