When training sets are performed to near failure, there is no significant difference in muscle hypertrophy between resistance training protocols utilizing 4 to 30 repetitions per set.

Study: Low-Load Resistance Training to Volitional Failure Induces Muscle Hypertrophy Similar to Volume-Matched, Velocity Fatigue

When you lift weights until you can't do another rep, whether you use light weights with lots of reps or heavy weights with fewer reps, you end up growing your muscles about the same amount—as long as you push yourself to the limit.

Study: Minimum load threshold in resistance training: insights into muscle metabolism, excitation, and fatigue across the repetition continuum

When people lift weights until they can’t do another rep, whether they use light or heavy weights, their muscles get similarly tired and stimulated — which means they likely grow about the same.

Study: Velocity Specific Adaptations to Three Widely Used Strength Training Methods: A Randomized Controlled Trial.

This study found that lifting heavy weights for few reps and lifting lighter weights for more reps both made muscles grow about the same size, as long as people pushed themselves to near exhaustion. So, you don’t need to stick to one rep range to build muscle.

Study: Similar improvements in skeletal muscle oxidative capacity after moderate (10-RM) and high repetition (20-RM) resistance training.

When people lift weights until they’re almost too tired to continue, whether they use heavier weights for fewer reps or lighter weights for more reps, they grow their muscles about the same amount. This study found that both ways worked equally well.