"Barcelona" is active with transfers, but registration is traditionally difficult.
According to Lent.az, citing foreign media, someone will have to vacate a place to comply with the 1:1 rule. Who could leave the club before the window closes:

Penya – 90 percent
Third in the goalkeeper hierarchy. Could terminate the contract.
Romeu – 90 percent
Not needed by Flick. Close to returning to Girona.
Christensen – 60 percent
The club is ready to sell him, but the player wants to stay.
Jerard Martin – 40 percent
There is particular interest from the Premier League, but he could remain in reserve.
Fermin, Casado – 30 percent
There is a risk of sale due to richness in midfield, but Flick is happy with them.
Araujo – 20 percent
He has a contract until 2031, he is not planning to leave. Only if a big offer comes.
August will be hot.