How to Build Confidence in Training

I think for the first like four or five years of training with my coach, I just tried to beat the top number in that place. And then I basically got fit enough and like developed enough as an athlete that like now that like I can, but I don't get stronger from it. So where does true confidence come from? Is it from a number? Because that's actually not going to work for me anymore. Instead, I would just like do it and be like, oh, that was really hard. Do it again. Man, it's still really hard."