I propose giving the creators of the groups the opportunity to choose whether they want not only trusted administrators to create tournaments in their group, but also ordinary members of the group can also create tournaments.
I will explain why this is necessary.
For example, I am the creator of a group. I created a tournament system, made a year-round schedule of competitions. This is my vision of the tournament life of my group and I may not want others to interfere with their competitions. Some players create spam tournaments and this affects the attractiveness and reputation of the group, this is also a good reason.
Now you can avoid spamming tournaments only by making tournaments open and barring other players from joining the group. But this interferes with the promotion of the group in the ranking of groups.
I think it should be a checkbox in the group settings, by clicking which the group creator can allow (or prohibit) the creation of tournaments by players in his group. However, developers know better how to implement this.