Belgium is a very good and experienced team, and I agree that they are favorites for one of the top two places in the group.
However, it will be very difficult for them to win the first place in the group against Croatia, who are currently playing very well and recently beat away France and Denmark in the Nations League.
At the last World Cup, Belgium was third in the world and Croatia was second, but while Croatia rejuvenated the team, older players are playing for Belgium, whose peak was at the 2018 World Cup in Russia.
I give Croatia a better chance of success at this world championship than Belgium.
To be fair to Belgium, they have some quality young players emerging as well. There are De Keteleare and Saelemeakers from Milan and Onana from Everton - all young and highly rated. Faez from Leicester as well.
Belgium still has a core of elite players playing on top of their game - they are near the top of my list of favorites to win. Croatia is good - I fancy our chances - but we'll be more of a dark horse than a serious contender.