How did (the cross-linguistic univerbation) 'nothing/not/none/no + less' semantically shift to mean 'despite'?
Several West European languages, most spoken in 2022, feature cognate adverbs with the meaning of ''nevertheless' by univerbating "nothing/not/none/no" +"less".
What semantic notions underlie their original literal ("nothing/never the less") and modern subsequent (despite something that you have just mentioned) meanings?
What does "not" or "none" refer to? Not what? None of what?
Is "less" here an adverb, pronoun, or determiner?
What does "less" refer to? What's "less" than what?
The key to “nonetheless,” “nevertheless” and “notwithstanding” is that they all require and refer to an antecedent statement, which may or may not be referred to elsewhere in the sentence. “Nonetheless” “notwithstanding” and “nevertheless” mean that what has been said or known (call it “X”) does not prevent, diminish or invalidate, etc., the fact that the primary statement “Y” is true, valid, etc. (“Limo services Los Angeles have been in demand for years. Nonetheless, their business is fairly limited…,” 10/01/11). The first statement makes the second “none the less” (or “never the less”) true.
"notwithstanding," early 14c., neuer þe lesse; as one word from mid-14c., neuerþeles. The sense of never here is "not at all; none the," as in unmerged expressions such as never the wiser, never the worse. In the same sense Middle English also had never-less (early 14c.), neverthelater (c. 1200), never-later (late 14c.).
"not the more or not the less on that account," 1839, none the less; contracted into one word by c. 1930.
Cognate Conjunctive Adverbs from other Western European languages
Italian has 'nondimeno'