This part nicely follows from what I've mentioned above. If Greece, or at least Athens, with its male-only inheritance system, restrictions on women being anything else than tradwives or priestesses (which, for the sake of argument, let's say is oppression rather than privilege) is anywhere near as patriarchal as Rome, which by default had a gender-egalitarian inheritance system if a Will hadn't been written, no known restrictions on women's occupations in the non-public sphere apart from an inability to be agents of banks, and divorces on demand by either spouse, are being described as similarly """patriarchal""", whatever that is even supposed to be at this point, then that just shows how meaningless that term is.
You describe it as "the degree of restriction" within a single system, but I'd more so say that it's a bit of a semantic trap. Notice above when I mentioned the researchers saying that a "true matriarchy" has never existed. Well, has a "true patriarchy" ever existed? How would those two systems even be defined? Is anything else than some hypothetical "true patriarchy" a false one?
No, it isn't

. According to social theorists, feminists and others, anything that is anywhere else than at some hypothetical far point of the "patriarchy" and "matriarchy" scale is just "patriarchy", no matter how mixed between the two extremes it is.