For building muscle, which you sooner or later need more of to be stronger, you need to either lift very heavy weights and come close to failure or do as many reps as needed with light weights to reach absolute failure.
Failure with heavy weights is easier than failure with light weights. After 15-20 reps your mind and lungs start to hurt, while the goal is to make the muscles hurt. If you give up before the muscles give up, you haven’t accomplished your goal with that set.
So, rep interval is of less interest - what’s important is going to failure with fairly heavy weights (1-50 reps maybe). It’s all about different methods of overloading your muscles.