If your wanting to build a bigger back then work your traps & your lats equally & don’t forget to work your Delts for that boulder shoulder width.
Key exercises include the Deadlift for serious mass, bent over row, wide grip pull up / lat pulldown & the lateral raise.
Look at a Low rep range “8-12” for serious hypertrophy. Your rest periods should be no longer than 90 seconds between sets, less if your working the agonist, antagonist. Focus on effective mind muscle control by maintaining tension for a minimum for 45 seconds per set, so perform each rep slowly. On your final set throw in a dropset or two personally I’m a fan of a 25% drop for max reps but mix it up.
Work the back once a week, twice if your an experienced lifter, supplementing or under 25.
Warning…Prior to lifting heavy, build your foundation first.
Prior to every back session, raise the heart rate, mobilise the joints and activate target muscles. Exercises may include Back extensions, leg swings, Bw squats GHD sets, clams, deadbugs & bird dogs for core activation.
Lastly….training with poor nutrition will lead to limited gains.