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.