As long as Pep Guardiola is still the coach of Manchester City, I think no one should underestimate Manchester City.
What happened in the Club World Cup tournament cannot be used as a reference and what happened last season was not so bad for Manchester City, they were still able to finish in 3rd place in the final standings and the problem they faced throughout the season was the many main players who were injured which affected the consistency of the team's performance and that is normal for a football team that oversees a long season.
For next season, I still really favor Manchester City to be able to win the Premier League title again, Pep is very experienced and he knows what he has to do, to oversee next season he has made many changes so let's just wait.
I will underestimate them because they haven't really do anything serious from last season. They are already push out of the World cup tournament, what's there to show again if not for the pre season and the season games and it's not like they have made incredible signing of players. I guess they are trying to play by the book not to spend more than what they earned last season, there will definitely be low bookings because they didn't have anything good to show the fans.
Lol this guy you're so funny

You seem to have easily forgotten how good Manchester City used to be, they have practically dominated the league since 2018 and have lost the title only twice to Liverpool. Don't forget the last time the lost the league to Liverpool they ended up winning it 4 times in a row so that's why they can't be underestimated at all. Having one bad season is normal and it doesn't mean they can't get better in the next season, we have seen them sign good quality players already to try and improve their team so I believe they will be better in the coming season.
The likes of Cherki Rayan and Ait Nouri are both good players that will add quality to the team.
All teams experience bad performance even Real Madrid experienced it too so there is no team too perfect, Manchester United was also once a great team in the league but things have not been so good for them for years now, they can't even remember when last they won the league. So take a chill bro, Manchester City will get better soon.