Diet is key, but you have improved in the squat, so how does that jive? As you said, most of the strength coaches known for getting their athletes bigger and stronger lift heavy and hard with fairly high volumes.
I have seen and spoken to dozens of athletes who have been stuck at a weight for long periods of time. However I have never trained or trained with anyone that this has happened to. Everyone makes progress if you lift correctly. You may have to gain mass, but if mass isn’t a problem, that makes it easier.
And to Pioneer’s last comment, I don’t believe you will plateau if you are…
- varying the rep scheme
- rotating exercises every few weeks
- taking recovery weeks