所谓 + [noun] + ,+ 就是 / 是指 + [definition]
所谓的 + [noun]
所谓 picks out a term so the sentence can say what it means. In a definition it opens the sentence, the term follows, and the explanation comes after a comma with 就是 or 是指.
The term often goes in quotation marks. In this use 所谓 usually stands without 的.
With 的, in the middle of a sentence, 所谓 says the writer doesn't accept the name. It does the work of English "so-called" or scare quotes.
The rest of the sentence decides which reading applies. If it goes on to define the term, 所谓 is neutral; if it goes on to contradict it, 所谓 is sceptical. 这就是所谓的… "this is what's called…" stays neutral.
The term comes straight after 所谓, and 所谓 is never a verb meaning "to call".
无所谓 is a separate word, "it doesn't matter" or "I don't mind", with nothing to define.