Actually I think Alvarez will replace Haaland because there are more players that can play in midfielder, Manchester City only have Rico Lewis and Oscar Bobb as substitute players lol. I have not yet see there's a club which lack of player because most of them are injured, so they only have 9-10 players which is not enough.
I think Pep Guardiola won't loss most important player Julian Alvarez who have special position not only as center forward but ability for playing well as second striker or winger position, I don't think Pep Guardiola will sell him to Barcelona regarding Kevin De Bruyne still injury and Julian Alvarez can replace well as attacking midfielder position. Manchester City midfielder looks not problem although De Bruyne injured because have Rodri, Kovacic and Kalvin Philip but its not good ideas have sell Julian Alvarez exactly he can play well on many position.
Left more than one month, Manchester City still not link yet with new player on winter transfer window although they have solid composition I think Pep Guardiola need several back up position if some time have player get injury.