To answer the OP’s question:
I didn’t choose to become Catholic or Protestant. I chose to become Christian after being a student of many different philosophies and religions.
I had accepted Christ as my savior in a Baptist church at about age 12, but during my teens I lost my faith altogether and instead became a seeker after the truth wherever I could find it. I looked at all the major world religions, parapsychology, various forms of paganism and New Age stuff, and many different secular philosophies, including Ayn Rand’s Objectivism.
After all that, I became an agnostic, almost an atheist (though I could never quite bring myself to say for sure that there is no God). I thought at the time that was where I was going to stay. But no… Alan Watts turned me on to Taoism, Zen Buddhism and Vedanta, and the truths they taught showed me that a merely material view of the universe was insufficient. I found pieces of the cosmic jigsaw puzzle that fit into a bigger picture.
In C.S. Lewis’ spiritual autobiography, Surprised by Joy, he explains how, from an intellectual rationalist skeptic starting point, he became convinced that first theism, then Christianity were true. He didn’t want to believe either, but the evidence was too strong. That’s what happened with me too. As with Lewis, the concept of “True Myth” (as explained to him by his Catholic friend, Tolkien) was key.
So… I became Christian again, at age 21, in college, 35 years ago. At the time, it was Protestant by default because that’s the only flavor of Christianity I was familiar with so I took that more or less for granted.
I never did think of Protestantism, Catholicism and Orthodoxy as different religions, just as different Christian traditions, all more or less equally valid. And now, I’m more familiar with all three, and that’s still my opinion. There are things about Catholicism and Orthodoxy I find attractive, some things I think they have right that we Protestants don’t, but I haven’t found them to be more true overall, else I’d convert to one or the other.