By the way, there is no teaching of the Church that says lay people cannot "understand the Scriptures on their own". (Why would we read them at Mass, if they were incomprehensible to the laity?)
However, my own personal interpretation of the Scriptures may be right or it may be wrong -- it has no authority in and of itself -- and the way to know if I am right or wrong is to look at the traditional teaching of the Church. Not "what the Pope said today," but the traditional teaching of the Church going back 2000 years.
This is no different at all from Hank Hannegraaf appealing on the "Bible Answer Man" to something he called "the historic Christian faith" in refutation of the odd heresies people brought up to him. The point is that the ideas you think you've derived from the Bible still have to be tested and found consistent with what the Christian faith has always taught.
Not understanding this basic principle is why we have liberal Protestant denominations trying to convince themselves and the world that God now approves of sexual perversions, where the Church (Protestant, Catholic, Orthodox -- I don't care) has always understood them to be abominations.
It's one thing to call words....but to understand the message of the texts is something else.
The Council of Trent sure seemed to come down against people reading the Scriptures on their own and trying to understand them. Highlights and comments mine.
Furthermore, in order to restrain petulant spirits, It decrees, that no one, relying on his own skill, shall,--in matters of faith, and of morals pertaining to the edification of Christian doctrine, --wresting the sacred Scripture to his own senses, presume to interpret the said sacred Scripture contrary to that sense which holy mother Church,--whose it is to judge of the true sense and interpretation of the holy Scriptures,--hath held and doth hold; [Page 20] or even contrary to the unanimous consent of the Fathers; even though such interpretations were never (intended) to be at any time published.
[I like this....Rome admits they don't have the positions of the ECFs on the Scriptures as they weren't published!]
Contraveners shall be made known by their Ordinaries, and be punished with the penalties by law established. https://history.hanover.edu/texts/trent/ct04.html
As the typical Roman Catholic is no where near versed in the myriad of writings of Rome.....how do you know for sure what you're hearing is correct?
We're back to the original question....how can you, a regular Roman Catholic, not a priest, understand the Scriptures on your own?