My favourite spurs are these ones https://www.smartpakequine.com/pt/german-style-blunt-spurs-7145 I have never had them rub any horse and they aren’t sharp or anything, which I appreciate. I also don’t find that most horses are offended by them like they are with sharper spurs like POW spurs. They were my favourite spurs for my TB.
I also second (third?) the suggestion of keeping your spurs really clean! I find that helps a lot with rubs.