As I’ve done throughout, I’m staying on topic, not going mole whacking.
"staying on topic," meaning if SS does not produce "universal unity, nor that it results in comprehensive unity," then it makes it invalid, was not my argument. For i addressed the premise behind it (as did the Lord in answering questions), which is that their is an alternative that does produce universal unity and comprehensive unity, that being the church as supreme but which is clearly shown to be false. Both are limited in the scope and depth of unity they have produced, while also seeing divisions.
Thus whether the unity in the NT was based upon the premise of a perpetual infallible magisterium, or Scriptural substantiation in word and in power, Scripture being evidenced as the supreme transcendent material authority for obedience and testing truth claims, is the issue.