Ultimately there is nothing they can do aside from make the rest of his time a living hell, which suits nobody.The wage cap is set by the league yes, but logically that would fluctuate on a clubs financials.
There is a figure constantly quoted of -144m, if Barca get enough cash in then logically that would move towards the green and give room to sign players & manage the wage bill.
Explained in great detail here. Ideally they want rid of course but what can they do? Drop him to the bench? Reserves? If he doesn't leave, not much else they can do.
https://www.espn.in/football/barcel...F9d5Orkb2i5CDLt6QdYSl6RvMURMLFdKdqa-5tnpzgyI0
the reports I’ve read all put their wage cap just shy of 100m euro which is set for the season so don’t matter if they suddenly fall in a bucket of money or not. If they can’t meet their wage cap some players will remain unregistered until they can. By selling frenkie it will give them wiggle room in the cap to add a couple more