BIGNJ has it right.
It's all food, gear and your own preference about how fat you want to look.
Oh you can't grow anymore? Eat more food. It works. It will always work.
But it's starting to just look like all fat? Ok, well then you need more hormones to tip the scale back in your favor.
And then—you might say you want to get big, but you realllly dont want to get big. The MAJORITY of dudes are this exact example.
The average gym guy thinks that getting big is just eating and building 100% muscle over night. No, no no. You end up getting chubby. To be the big you want, you need to be chubby. And hold on to that chubby for way longer than you'd like to. AND THEN CUT. It's a long game that 95% of dudes are not willing to play. Most guy will spend years just recomping slightly and getting to a good physique. And then, in reality, you cant really do that recomp shit anymore. You either need to cut down or get big the hard way. You MIGHT not be willing to get big the hard way. And that's ok. Just realize that those big gains are in your past. Its fine tuning what you have now.
EVERY PERSON has the ABILITY to get huge. The few who do, realllly want to.