Nice post, you hit on the nub of many conflicts online today. That being, this line: "I also remember that some beliefs I have held in the past, I no longer embrace, which is a graceful way of saying I was wrong". Today, especially online and with certain topics, people are right-fighting. That is, the disagreement/argument comes down not to an exchange of views, but one or both participants trying to insist they are right, and the other is wrong. It's a really great way to learn nothing.
A stance on an issue is rarely a life and death moment. What's needed is some perspective. At the very heart of say, science, it's not about being right about something, it's about testing scenario's, taking in new information as it arrives, testing things you know will fail, because a failure can tell you as much as a success. If doubt is cast on a theory, you go back and look at the theory and adjust as you go. But in online "debate", I too often see right-fighters, and when they get frustrated, they essentially rage quit. It's just another way to bury your head in the sand.
You've been wrong, I've been wrong, and in fact, we've all been wrong about something. I'd of hoped this would have led to some humility, we surely know we
could be wrong about something, right? But nope. And I don't think this is entirely down to the individual, I think it's partly down to the way Social Media works. For example, it's easy to fall into the trap of believing that if you get more likes than an opposing video, you are clearly "right" and more popular. But Likes are a construct of the software, they're not necessarily telling (it can be trivial to bump up your views and likes on some platforms). And so it goes. So opinions become a popularity contest.
Add on top some who internalize their beliefs as though they're sacrosanct, immutable, and beyond reproach, no matter what, and you start to get personalities shaped by ideas in crazy ways. As you say, being wrong can happen, and there's nothing wrong with that as long as you were both sincere, and have some humility. As such, debates can actually be fun and enlightening, rather than full of rancor and abiding hatred toward someone else.