My arms are getting strong. You don't need much volume if doing 5 to 6 days a week. Generally 2 sets each. 10 to 12 sets per muscle a week is all you need.
Sometimes i do 3 band rows with 1 arm for 8 to 10 reps. Another day 1 band for 40 reps.
Mix it up. Anywhere from 6 to 40 reps builds muscle.
(Sometimes i train twice a day)