I don't think it's right to say that they will definitely lose. Because we can't know these things before the match is played. Any effective match can change the fate of the match. For example, a red card that can be seen by the opposing team will put the opposing team at a great disadvantage. Manchester City has not been successful lately, yes we know that, but maybe they will be better in the future under Guardiola. Guardiola currently has a period of rest ahead of him. I think he has the capacity to use this period in the best way and turn the team into a more energetic and well-playing team.
There is no time to rest for Pep Guardiola when he knows his club is in trouble he must be thinking hard to be able to restore Man City's performance as a strong competitor in the UCL. Indeed currently Man City still rested for UCL match but they still have a schedule in the Premier League and Pep Guardiola still has quite a lot of pressure, in the transfer window later Pep Guardiola must really take advantage of it to recruit the players he needs I am sure Man City still has a chance to qualify for the last 16 of the UCL.