I believe there is a special case for Zero carb … or diets approaching zero carbs, where you get to use more protein to make glucose. Normally we need to make 80g of glucose and we can make that from 20g of protein.
Someone eating 20g of carbs a day, only need to make another 60g so their requirement of protein drops to 15g.
Someone eating 40g of carbs a day, only need to make another 40g so their requirement of protein drops to 10g.
Of course that’s just protein to make glucose, you’d still need your minimum required for protein turnover - but at 3g you are probably OK there