Quoting you, OP, because I don’t think you’re giving yourself enough credit for getting this far with a highly reactive horse who has had genuinely scary melt-downs. You should be patting yourself on the back for getting an award on a horse who once couldn’t handle a pole–don’t minimize this because of the size of the show!
It sounds like the people you ride with (such as on the trail ride that went wrong) or who are at your barn have an expectation that you should have no fear (“man up”) while you’ve had a number of experiences that would make even a level-headed rider fearful. Even getting your mare home safely walking in hand is a credit to you.
There is absolutely no shame in minimizing risk. You know this horse and have worked with her for years. I think there are some horses (like some people) who are just by temperament scaredy-cats whose first instinct is to bail. It’s obviously helpful for a wild prey animal to run first and think later, but not so much for the rider. The question is if the mare’s good qualities outweigh the extra work you will likely always have to do, to do normal horse things with her. It also might be that the barn isn’t a good fit, if everyone there has an expectation that all horses have to be “fine” with all the stimulation life throws at them, including a herd of horses cantering away.