Sub max work is good for improving your technique, AMRAP sets are not but they are better for hypertrophy. You have to push close to failure (at least 3-4 reps short) to stimulate hypertrophy, but if you do sub max work in a cluster set format with short breaks then it can be useful for hypertrophy as well. You will have to do more volume for the same hypertrophy, but you have the added bonus of technique improvements/neural efficiency.
Most people will do better with some volume, there are some lifters out there who only do one work set (Lilliebridge, Oak, Karwoski) but their technique is already solid and most of them do some bodybuilding-type work. More drugs = less need for volume to build muscle, but either way technique is a major factor.