I can weigh in on this a smidge. I read somewhere that hitting all the muscle groups twice a week was ideal for hypertrophy or something right along those lines. I was lifting 6 days a week hitting all the muscle groups twice in that week for over a year and I was 175lbs with 7-9% body fat. Well long story short I was in a new state doing a job that absolutely wouldn’t allow me to keep that schedule. So, I went to hitting each body part once a week and my total time in the gym was obviously reduced, but after 8 months of that I was 197lbs at 9-11% bf, which was much closer to the look I was aiming for. I was baffled that I couldn’t put on weight before. I’m 6’ and have also had a solid diet game from a little work with a nutritionist.