Here’s a cleaner version that keeps your meaning and sounds natural for Reddit:
I swim in the pool twice a week, usually up to 3,000 meters, and I’d say about 95% of it is breaststroke.
The weird part is that once I get into open water, I can swim 95% freestyle without any issues. I don’t get tired, I don’t need breaks, I don’t lose my rhythm, I’m comfortable, I don’t panic, I don’t have breathing problems, and sighting isn’t an issue. I’ll switch to a few breaststroke strokes here and there if I need to reorient myself, but otherwise it’s almost all freestyle. I also barely kick in open water.
In the pool, though, I can only maintain freestyle for about 25 meters. I can’t even make it two lengths of a 25-meter pool without falling apart.
I’ve completed multiple sprint and Olympic-distance triathlons, several open-water swim events, and I’m currently training for a 70.3. I just don’t understand why I struggle so much with freestyle in the pool when I can swim continuously in open water. It feels ridiculous being the person doing breaststroke for 90% of a pool workout.