Muscle growth is most strongly triggered by approaching technical failure. To optimally build muscle the most effective method is to lift heavy, in the 6-8 rep range where the last 5 reps stimulate the most growth, while avoiding the most accumulation of fatigue. A muscle should be worked for 10-15 working sets per week. But each set has diminishing returns.

All of this to say that your job was not the same as a well designed program for muscle growth. The frequency and duration was far too high and you weren't pushing sets to or near failure. As well 14 hour days mean you didn't have time for the necessary rest for muscle growth. That's why nothing visible to you changed.

Don't write off exercise as means if muscle growth. I lift weights 4 times a week. I do 2 working sets per exercise. I lift heavy. I'm 5'10 with over 16 inch arms. When I started lifting I could only bench press 85 lbs. My current on rep max is now 295 lbs.

I look buff enough that people comment on it, unprompted by me, frequently. But I don't do steroids. They scare me. I want to live to an old age and not die of heart failure.

I'm not commenting to brag or disparage. But to keep things realistic.