Read a study the other day that took two study groups. One did 3-sets to failure at 80% max. The other group did 3-sets to failure at 30% max. At the end of the study, both groups gained on average the same amount of muscle. I am assuming this tells you that lifting heavy does not always amount to more added muscle, that the key is taking the muscle to failure, even with a lighter weight.
The conventional wisdom is that heavy/low reps is better for strength improvements, while more reps at a lighter weight is better for hypertrophy/muscle growth. That’s been my personal experience, as well. In both cases, working to “one left in the tank” is key.