The randomness here lies in the random selection from a predetermined number of players by the organizers for a random draw. Each bracket was also generated randomly. This means that players were randomly distributed from each bracket into groups, and this is the optimal option.

The distribution into brackets is not random, but rather based on the organizers' assessment of each player's skill (I was surprised, for example, that Tvarina ended up in the second bracket, and Amilu in the third (if I understood the principle of group formation correctly, that's how it was)). The distribution into groups is not random, but rather designed to avoid repeating castles. The percentage of randomness in this "draw" remains small. I have no complaints about the organizers, I just don't see much randomness here, as the organizers did a lot "manually."

p.s. No criticism, I was just nitpicking about the word "random" :D