With all respect both parts of this statement can’t be true. Within 3 weeks you can’t have played around with many different reps/set. At least not to a point where you know what works. Or feels good over a period of time greater that few hours. That’t not to say you’ve not done good work. But 3 weeks is a toe in water time scale. Don’t dismiss other training parameters just yet.
With regards to work out length - I’ve had workouts last 15-20mins. They are not massively effective. I’m not making the best progress. But they work to retain / moderately improve my strength / size.
My current workouts are 90mins. I can not see how people work out for longer. I’m done at the end of these. 100% spent.
100% agree with this. There is NO way you should be on 1700 calories at 260lb. See this from Eric Bach. You should be on 2 times this.
EDIT in put the link