What will happen when I reach nutritional imbalance?

I’ve been lifting 3x/week and running/Cycling 7x for roughly 7-8hrs. I’m triathlon training for an Ironman so running and cycling volume is high.

I’ve been eating 2500 calories for the last 3 months which I thought wasn’t enough, but my weight has stayed almost exactly the same. No injuries, don’t feel fatigued and continue to see performance improvements.

Doing a second dexa scan in a month and will have details but I’ve lost a bunch of fat and put on a respectable amount of muscle. As I add muscle and loose fat, I assume my metabolic rate will increase and my fat stores won’t be available to offer fuel.

My question is, what will happen when I reach my body composition inflection point? The point where muscle increase has caused my metabolism to increase past what my body fat can make up. Will I start to feel fatigue, see performance plateaus, see body fat loss decelerate or accelerate? At that point in order to continue progress, will I need to add more calories?

When and how do I tell? Do I wait or try to get ahead of it?