If you have plateaued in gaining I suggest you take a few weeks off from whatever exercise you were using and implement a different exercise, something less intense. After a week or two your body will reset and you’ll be able to gain using
LM again. There is no stronger way to stretch and when you consider this type of intensity it makes sense that every once and again you should take a small break to reset things. So a lighter exercise for a couple weeks will do just that.