Apparently this is a big blow to Guardiola's ego, so he is trying to justify it with his past achievements. At the moment, it looks like he'll have to turn to the past more than once to console himself. Will he have enough strength to work until the end of the season and make a real restructuring of the team? It is difficult to say. He always worked in hothouse conditions and when he had real competition (with Mourinho) he quickly lost it and ran away.
Whether this is a coincidence or not, the decline in Manchester City's performance is also in conjunction with the decline in Real Madrid's performance as we know that these two teams are rivals in large leagues like UCL but this time even in their respective leagues it is very questionable to get their victory.
He said that he had gone through a lot with Manchester City was as proof that he had the ability, with other implied messages that we could read he needed time to change again, and could rise again from this bad time, some of his strategies were very old -fashioned And the players are not so creative in building attacks, they seem to lose confidence on the field.
I don't think there is any analogy between Real and City now. Real is first in La Liga (with one defeat), and City is 5th in the Premier League (with 4 defeats and 11 points behind the leader).
As for injuries, all teams suffer from them, but somehow cope. The nosedive that City has found itself in is unprecedented.