“And there is no indication Matthias was chosen by Jesus but by 11 men who overstepped their authority.”
Nay, not so. Peter, speaking by holy spirit and acting as a prophet, explained the prophecy indicating Judas would be replaced. Evidently with God’s approval and direction the lot fell to Matthias, who is accepted as one of the twelve.
Soon after holy spirit produced “signs and portents through the apostles”, Matthias included, so their choice was confirmed as was their authority to make such a decision.
There after Matthias is recognized by Luke when he, writing under inspiration of God, spoke of “the twelve” at Acts 6:2.
Therefore the Scriptures do not support your contention that the apostles acted outside their authority.
Bear in mind this is supposition on my part. I believe the choosing of the 12 was reserved to Jesus alone and the duties of the Apostles was clearly delineated by Jesus. This duty did not include choosing their successors. They were fallible men.