“What Protestants do is divorce teh bible from the magisterium, arguing that Scripture is inspired - but the Magisterium has no authority. This approach has some severe difficulties. “
The difficulty I see with the RC way is that men are fallen.
“All have sinned and come short of the glory of God” (Romans 3:23) “There is none righteous, no, not one; There is none who understands; There is none who seeks after God.” (Romans 3: 10-11)
So depend upon a Magisterium or any other group of men to decide what is Scripture and what is not, or what the Scripture particularly says; particularly when they add in things that are absolutely not there; and especially when they add in things that really are forbidden - this is a problem.
Scripture, being God’s very word, is infallible. Men, being fallen, are the definition of fallible. Thus I don’t think it is right to depend upon the Magisterium over the authority of the Bible.
Some believe Protestants reject all church authority. Some indeed may. However, I certainly don’t. I do believe the Bible ordains legitimate authority, to exercise church discipline and dispense sacraments and have authority within the church. We in our church agree to submit to them, but with the caveat - within the bonds of Scripture.
Is this a good summation? (Serious) Protestants believe that the Bible prescribes what church authority there is. (Serious) Roman Catholics believe that church authority prescribes what the Bible is.
The problem with your opinion is that it presupposes an infalliable bible written by falliable men. You can’t get from falliable to infalliable - but you can get from infalliable to infalliable.