although UEFA has made this tournament as competitive as possible, many countries consider the UEFA Nations League event not so serious, so it is only natural that many great countries have to fall from several dark horse teams, even though there are trophies up for grabs for the end of the season but many countries don't want to take this competition more seriously like the EURO or the World Cup, maybe we really hope that in the next 2-3 years the UEFA Nations League will become a more serious competition for European teams to participate in.
I also think that's what will happen, in a few years the competition will become more relevant.
Even because apparently, they want to extend the competition to countries outside Europe - hence the name. But first they want to understand the impact this has on fans and national teams.