Just to clarify, you have made a few references to your loads like…
This range will be 4x8 @ 80% of 8RM to build some muscles.
At first I thought this was a typo. While 4 x 8 at 80%(which is about an 8RM) would be very tough, it would be of little value for hypertrophy if you are actually talking about 80% of 80% (64%) which is a 14RM load, give or take. That’s too light for hypertrophy using the sets/reps you discussed.
In later posts, you say similar things, (80% of 6RM, 80% of 5RM). Make sure you understand which rep/load ranges work best for which training goal (hypertrophy, strength, power) and that in general, we talk in reference to 1RM, i.e. >85% of 1RM for strength, 30-70% of 1RM for explosive power, etc. The ranges are debatable, I realize, but keep in mind when reviewing the training of others that their percentages are based on their 1RM.