The default browser can definitely be changed. I’ve got mine set to Firefox.

I was a mod on a larger subreddit (~4 million users) and it was honestly as boring as you’d expect. The most fun was just hanging out with the other mods because they were fun people, but they might as well have been someone I met doing an activity that was actually enjoyable. I lasted about 4 months before quitting, because I found myself spending more time moderating than studying, which didn’t seem like a healthy way to spend my life.