I have addressed this point elsewhere in this thread, and it has also been explained ten thousand times on forums such as https://reddit.com/r/carnivore

The long and the short of it is that fresh meat contains vitamin C and the carnivore diet also reduces your body's need for vitamin C because vitamin C is used for the synthesis of collagen and you will be getting collagen directly by following this diet.

You can read more here: https://www.kevinstock.io/health/do-humans-need-vitamin-c/