The club probably knows what it will take to renew him, and I suspect it is why they are hesitant.
He could be a very expensive backup CF if we manage to get Alvarez or Pedro. And they are fairly comfortable risking losing him for free than tieing him long term and then not being able to move him out.
Ferran is likely to be like Frenkie. He will either renew and stay, or leave for free, he was never going to accept being sold, rather wait and enjoy the City and then and collect bigger pay. So sale isn't really an option either way.