In terms of La Liga next season, there is no doubt that Real Madrid will win and retain the title. Barcelona is indeed a big club, but as you said, its current squad is not as optimal as before. Girona, last season was really good, but it seems like some of their top players were targeted and left the club.
If someone who doesn't know anything about football see when you people about how certain it is for Real Madrid to win La Liga next season, the person wouldn't believe Barcelona won it the season before last and Real Madrid won it last season. Barcelona won that league when they were going through a financial crisis mind you.
Real Madrid are favourites to win La Liga, that's a fact, but why does everybody believe they're invincible with Mbappe? Is the attack the only part of team? I mean, this is Barcelona we're talking about and recently, they've been getting their affairs in order.With Flick, Barcelona stand a very big chance for next season's la liga. With the players he has and the players that Barcelona will sign, we would witness a very competitive la liga next season. As good as Real Madrid may be, I do not underrate Barcelona.
To be honest when we compare Madrid squad with Barcelona squad it is easy to understand that Barcelona squad is far behind Real Madrid. I agree with you that it is not possible to win titles depending on attack alone. However, Madrid's entire squad was very stable last season. And their only weakness was their attack. The performance of the attacking players was somewhat erratic. Even then, Real Madrid won the Champions League and La Liga titles despite Ancelotti's excellent match tactics, despite a weak attack.
Hansi Flick will definitely try to stabilize the Barcelona team next season. However, the overall condition of Barcelona is now unstable. Both Barcelona's defense and attack are relatively weak. So stabilizing the entire team is going to be very difficult for Hansi Flick. Competing with a stable and strong squad like Madrid will make it very difficult for Barcelona to dominate La Liga next season.