It is indeed very interesting to talk about Nico William and Barcelona, because he is one of the top players that Barcelona has wanted since last season, but it has not materialized. Meanwhile, Barcelona must buy him according to the release of Calus from Bilbao, and on the other hand, Nico's contract in Bilbao is still until 2027.
And the problem is, now La Liga has also warned Barcelona to be aware of La Liga's rules, regarding player salaries and registration. This happened because of complaints from Bilbao as conveyed here:
...

It doesn't look like Athletic Bilbao has complained about the situation.

The source is Fabrizio Romano again so this very awkward...
He is still keen on completing the deal. Barcelona is only needed to pay for Nico's release clause and that's it. They just don't want any installments like I said before.
I hope Barcelona finishes it without making a regulation breach.