But...that's not even possible. There are some Parishoners who will go astray, even some Priests, but the "Church"? Jesus founded the Church. It will be here until the end of time. It is not possible to "walk away".
The “Church” is not the Catholic Church. It is the communion of saints. Not sure where the Bible talks about the Catholic Church, where I was a member for 35 years, being the Lord’s Church.