@kutloello This is where crossfit points you to the direction where you want to go.
- What you did not say is how old are you?
- How is your technique when you run? Is it on point or you think is on point?
- How about your do gymnastics? Is it on point or you think is on point?
- What about your technique in general? Are you sure youre not losing energy on suboptimal technique?
Lastly, you mentioned being last on wods, do you scale? Do others scale?
On a high level (think games athletes) you have to balance your weight with muscle/cardio capacity. I doubt that you're there just yet, otherwise you would never ask these questions, you'd know the answer to them.
As someone said, you're a big dude in general, so that makes your body sub optimal already for high end competition. Look at elite males, none of them are super huge, they are all... well... average height, sometimes on the short side (Fraser!).
I bet you nail the rowing/bike stuff.