He was a bit rushed into this position, and LE helped with giving him the start so early too (and Gavi himself helped by playing so well in these games)
Whether these quotes by Busquets and Xavi that I read the other day were fake or not, I agree with them that he has a lot of habits and weaknesses that he needs to improve and change, he is very much an unfinished player, and he is not good enough to start every week for FC Barcelona currently.
But since he was brought in, and played so much, he is in his right to demand a lot, and his next contract will be on the level it should have been in the next negotiation two years from now. It is not good for the wage structure, and his next contract might be a problem if he continues to play well enough (gets playing time and "reputation")
It is well within the realms of possibility that he will be a Sergi Roberto level player 5 years from now, but with a contract that is twice as big.