There is no essential carbohydrate, the body can derive any glucose it needs from essential fats and proteins.

That said, I'm keto and find it difficult to stay under 30 grams of carbohydrates per-day simply because carbs are in so many foods. I've, a few times, gone "strict" keto i.e 10g< of total carbs per day which includes indigestible fiber and I (anecdata coming at you) felt great.