@cinnamoroll Then you are either not 1. training hard enough or 2. with enough volume or 3. often enough. It’s at least one of those 3 if not all 3. If this were just a brief plateau it could be other things, but not if you haven’t progressed long-term.
Assuming you’re fueling your training with enough protein, food, sleep, and stress mgmt, your results are going to be directly related to a simple calculation:
Volume x Intensity x Frequency
(Note: Volume and Frequency are obviously straightforward, but Intensity primarily means 1. effort & difficulty + 2. proximity to failure.)
Once you understand that, it makes things very simple: if you’re not gaining muscle, you always know why; at least one of those 3 values is lacking.
Simple as that.
(Assuming you’re training with hypertrophy rep ranges; 5-30 reps per set; primarily 5-15.)