Matt 16:18 "...and the gates of hell shall not prevail against it."
Gates are defensive, not offensive.
That does not mean that hell will not overcome Catholicism or any other religion.
What it means is that the church, the true body of believers in Jesus, will prevail over even the gates of hell . Satan and his demons will not be able to stand against the church when it moves and does the work Christ commanded it to do.
Claiming that is means it’s a promise of God’s protection of the Roman Catholic religion is a complete misinterpretation of that verse.
And considering the fact that for centuries, and maybe even over a millennium, now, the Catholic religion has been infested with homosexuals and has a long sordid history of child abuse, there’s no way anyone can make any credible claim that Catholicism is being protected by God.
That would mean that God is condoning and tolerating sin of the worst kind in His church and that does not happen.
For precedent, see Revelation 2&3.
Catholicism has not only not overcome the gates of hell, for too many of its victims, it became the gates of hell.