Are you planning on doing this heavy athletic training during your period? I know nothing about any training, just to be clear. If you take a break or reduce your activity, it makes sense to adjust your eating, too. I think it would be better for you to stop grazing and stick to your eating window. Alternatively, you can expand your eating window during your period. You could probably have more freedom with your choice of food, but for me, protein, fat, and then carbs work best. My general advice would be to go gentle on yourself during your period. It’s challenging enough.
Cut down on simple carbs like sugar, and include longer carbs like rice or beans and other legumes and vegetables. I’ve done keto and slowly added rice. Felt amazing while on keto.
But keto and IF is pretty tough to do, so just do IF, and when you crave carbs eat just the more complex ones.