I have been on a keto diet for several months and had great success. I am leaner, stronger, and a bonus is I have clear skin for the first time as an adult.
In a month I am competing in BJJ for the first time. A couple years ago I was running ultras and trail races and placing and doing well and I had a tradition of high carbs the day before, though I think a lot of that was psychological.
All that said. Is there any benefit to adding carbs in competition week or day? I THINK I will be safe enough within my weight class for that not to be a concern.