I suggest strength and conditioning like a wrestler. Maybe taking up Judo too. Judo guys tend to be really strong.
Doing a lot of BJJ would help also since it is specific to your goals. I've tapped stronger guys that outweight me by 30 pounds because I have better technique and good conditioning. When I was doing crossfit and BJJ I just burnt myself out. I didn't want to get out of bed some morning lol. So sore and tired.