He said “Non-Catholic Christians” which could include E Orthodox as well as Protestantism of all stripes. Don’t all these Non-Catholics use scripture? Yes. So restricting this answer to scripture alone is the challenge proposed by the opening question.
JonNC:
Why the limit. Lutherans don’t use it. Anglicans don’t. AFAIK, Methodists don’t. Why set such an unnecessary limit?
That limit is the requirement of the OP. Therefore that is the challenge .
Can you show me where any pope out of 266 from Peter, left the Church and stated his own deal?
JonNC:
It could easily be argued that the Bishop of Rome schismed from the rest of patriarchs.
The position Jesus gave Peter, was unique, and was shown in a previous post
Here
BTW, one of the titles of the pope is “servant of the servants of God”
There is something else required of those he leads, and it is in the definition of the word and understanding of the word used in Lk 22.
emphasis mine
[2233 /hēgéomai = to rule (“an official who leads”) carries important responsibility and hence “casts a heavy vote” (influence) – and
hence deserve cooperation by those who are led (Heb 13:7; passive, “to esteem/reckon heavily” the person or influence who is leading).]
IOW others he leads, owe the pope the cooperation, and esteem, for his position