You are confusing a lot of things right now.
Back in the days of the OT, before Christ came, people weren’t saved yet. They went to the “Bosom of Abraham” which was a special place in hell where those who died in God’s favor were protected from the pit of the damned. However, the Jewish Church was the true Church of God. Then when Christ came, he fulfilled the Old Covenant rendering it’s laws moot, meaning that anyone who followed Christ were freed from the Old Laws. Christ established new Laws and established a new Church that became the new one true Church of God (the Church of Christ), which is the Catholic Church. After Christ’s death, he freed the souls in “Abraham’s Bosom” who were resurrected with him and walked among the people. Then Christ took them to heaven with him. They were saved by Christ, like all those who are saved are.
Now, for those left alive after Christ’s resurrection, it was through the Church that people are led to Christ to be saved. So, salvation only comes through Christ’s Church, whose visible body is that of the Catholic Church. But there are those who are not part of the visible Church, but still a part of the invisible Body of Christ (the invisible Church). The invisible Church consists of those who sincerely try to follow God and Christ by way of his visible Church, but may also consist of those who sincerely try to follow God and Christ, but are outside the visible Church.
Now, this means that it is possible to be saved while outside the visible Catholic Church, yes. However, the farther from the visible body of the Catholic Church you get, the less likely it is. So, possible, yes, but not as likely. So, to become a part of the Catholic Church and follow Her teachings is to be more assured of your salvation.
The analogy I like to use is people on top of a mountain that are to trek down the side of the mountain where the goal is to get down as safely as possible. There is an experienced guide at the top of the mountain. If you do all that he says, you will make it down without harm. If you only half listen to what he says, while you may make it down alive, it would not have been a pleasant journey as you would likely sustain some injuries on the way down. If you are following the group down, but not listening to the guide, there is an even less likely chance that you will make it down without injury, and you could possibly misstep and not make it down alive. And if you completely ignore the guide and go off on your own, making your own path down the mountain side, it is least likely that you’ll survive the trip. You may even decide the best way to get down is to just jump off the side of the mountain. Even though there is a slim chance you could make it down alive, it wouldn’t be without injury, and it wouldn’t be something that I would place my bets on. I’d rather stick with the experienced guide and do my best to follow what he says, so that I am most assured that I’ll make it down alive. I’ll likely fail to listen sometimes, and maybe scratch my knees, but as long as I keep at it and do my best, I’ll make it down.
Christian freedom? What do you mean here?
Now that made me laugh out loud.