Barcelona might be interested in Mohammed Kudus these days. However I don't think they would be free to sign new players in January according to the La Liga financial rules. They just need to sell unnecessary players in the team to raise some funds. They aren't in need of any transfer now as they already have a very qualified squad.
Besides it is said that Kudus is more eager to sign for a Premier League team rather than the others.
According to Barcelona's sporting director Jordi Cruyff, they have been following the development of Mohammed Kudus for more than a year, but there is no certainty on the part of Barcelona to sign Mohammed Kudus at least for now. Mohammed Kudus is still under contract with Ajax Amsterdam until 2025, the value of Kudus release which is estimated to be around 50 million Euros is a consideration for Barcelona because their financial status is not healthy.
Barcelona already has a solid squad at the moment, the Barcelona players who appeared in the World Cup are also very good. Barcelona doesn't need to bring in other players in the January transfer market, they can still take advantage of existing players to face the competitions they are still following.