Pellius, never mind what protocols you tried, what did you end up believing worked for you to grow?
1. Training intensity. As long as you keep working within your functional ability, exercise will do little or nothing for increasing size and strength.
You have to try to subject your muscles to a stimulus it is unaccustomed
to stimulate an adaptive response.
Most people I see at the gym just keep doing the same things over and over. They terminate a set when they could have easily done another three or four reps, if not more. They are there daily like clockwork hitting the same machines at pretty much the exact same time doing the same amount of reps and weight going through the motions like a mindless robot glancing at their phones or the TV, and have been doing that for years. Yet, and I am not exaggerating, there is nothing about them that would even hint that they've ever lifted a weight in their life.
So much wasted effort.
2. Recovery. When you tax your body to extent that an intense resistance training does you first have to rest enough just to back to where you started before the training session. Then you must allow an additional recovery period to compensate/adapt to that training stimulus. Big muscles are low on the priority list and other systems taxed just from day to day living that everyone experiences will be addressed first. Even without resistance training, everyone needs adequate sleep just to maintain daily function.
How much recovery is needed is subject to debate and I'm sure various from individual to individual.
3. Nutrition. Adequate nutrients, most notably being in a caloric surplus, is absolutely necessary to increase overall muscle size to a significant degree. You can't build something out of nothing. What is the ideal macronutrient profile is again subject to debate but you can't build muscle out of carbohydrates or fats. Only protein. How much? I don't know what is ideal but you should err on the side of more than less. If you ingest too little protein you compromise optimal muscle growth. If you ingest too much it's still used as calories.
But, at the end of the day (my least favorite expression), it's your genetic predisposition that determines how far you can go. You can follow the most optimal training and lifestyle protocol most conducive to muscle hypertrophy and still never look like an advanced bber. Then you can have someone that throws weights around, or maybe just works in a physically demanding job or sport, and looks six weeks out stage ready.