Can they still buy players? After spending incredible money last season. Not to mention that with the salary list of each player, they will need a lot of money. It looks like it could violate FFP rules. This season Barcelona proved a failure for the UCL, with the same player Xavi may need to improve the mentality of the players. Rumours Messi will return, it looks like it could help them in the UCL. But now that won't happen, it looks like Xavi has to look for non-star players with good games and low prices.
Even though Barcelona has complicated financial problems, but I think they can buy some of the players they want, certainly not about Messi. Xavi has shown enough interest in plans to bring in a defensive midfielder to replace Busquets, that is his priority at the moment and maybe he will get one. Regardless if it's a star or not, but I think Xavi will try to get it next season.
It seems that the League has not yet lifted the restrictions on Barcelona and in order to buy someone some players will have to get rid of (even taking into account the players who have already left). Today I read that Javi has some difficult choices (who to keep who to sell/let go), but in any case, he will have to make these choices. An unpleasant story, but Barcelona itself is to blame for driving itself into a pre-bankrupt state.