Straw Man on your part.
I am not putting “the Protestant idea” into anything. /roll eyes. You are the one divisively separating this into Protestant/Catholic.
Pentecost did not save them. They were already saved before the Day of Pentecost. Speaking with tongues did not save them. Being baptized in water did not save them (a Church of Christ belief). Believing in Jesus saved them.
Romans 10:9-10 “If thou shalt confess with thy mouth the Lord Jesus Christ, and shall believe in thine heart that God hath raised Him from the dead, thou shalt be saved.” Period.
No strawman. I speak the truth.
“Unless you eat my Body and drink my Blood you shall not have life everlasting.”
Gospel of John: Discourse on the Bread of Life.