I don't know how bookie determined the odds for each teams because France as the previous champion should be first favourite but they have high odds than England or Brazil
You need to look based on their performance in this year, France right now at position #4 on UEFA Nations League A, however I have no idea how can England become favorite number 2 since they do have bad performance like France.
IMO a good club need to have better both offensive and defensive players, because the favorited clubs are mostly have good offense but weak defense e.g. France, England, Argentina. As we know both Benzema and Mbappe as the best center forward in different club didn't work if they placed in the same club.
I'd say either Brazil, Spain and German will win this year FIFA World Cup.
I think that the results of France or England in this year's League of Nations are not too relevant and an objective indicator of the strength and quality of these teams.
The League of Nations is an unimportant competition, something between friendly and unofficial matches, and for the strongest national teams this competition mainly serves as a preparation for world or European championships.
So I wouldn’t worry too much about the poor results of France and England, and I think both national teams along with Brazil, Spain and Argentina are still favorites for the world title.
About the issue of odds or the favorite team for me is not too important, because even if they are favorites you will have your own choice in betting. So even if the team that should be the first favorite turns out to be at the bottom, then at least you will get better odds, right. Also, the team's performance from time to time will certainly change and this is the factor that makes the favorites always change, for example in this year's championship league, where Madrid are not favorites but they can win the title. Therefore, the team that is the defending champion will not always be the favourite, there are many factors in the related assessment of odds and which team will be the favourite.