I feel like I’m not working out hard enough

I’ve been hitting the gym 3 times a week for 3 months now and I feel like I could do better somehow and while I can’t see much of a difference physically (or it’s probably body dysmorphia) here’s some things I have noticed:

My mood and mental clarity have significantly improved since I’m always happy when I’m done doing a workout 

My stamina has increased (although it would probably skyrocket if I quit nicotine) 

I’ve gotten significantly stronger and can really give a punching bag a good huss huss lol

I’ve been able to put on more weight than I ever been without looking chubby/fat (for reference 150 pounds used to have me looking chunky with a belly, neck was less visible, my face was puffy, and it felt very cumbersome to move fast but now I’m 152 pounds while being fast and agile). 

But I feel like I’m expecting too much to change with all the effort I’m putting in since I’m going to the gym consistently, I have a workout routine that I follow in different orders depending on the availability of the machines I use, I’ve been increasing the weights every single week and have been able to rep the weight 15 times before deciding to graduate to a heavier weight, and I have a decent diet chocked full of protein.

My goal is to be strong as hell and have a superhero build so honestly any advice/tips would be appreciated and probably help me level up to the next stage of my fitness journey :D