At the moment, I think the following option is the best.

Stage 1: Swiss-system tournament with 4 rounds per week. Might and Magic factions play against each other, with the first round being random, and subsequent pairings determined randomly based on the number of points, without repetition. After 4 rounds, in case of a tie in points, the winner is the one who defeated stronger opponents, with a coefficient as in the previous tournament. If this is not enough, additional games are played. We select the top 8.
Stage 2: Playoffs. 1 from Might and Magic against 8 from the Hive, and immediately create a bracket up to the final. It doesn't matter which faction wins; afterwards, everyone plays according to the bracket, with Magic factions playing against Magic factions and Might factions playing against Might factions if that's how it turns out. And even if the top spots end up being dominated by one group, for example, the top 4 spots are taken by Magic factions.

And most importantly, in my opinion! With this scheme, there are 8 rounds, 4 in the group stage, and 4 in the playoffs. Each participant should play 1 game with each faction in each stage. The factions are determined before the game by a judge, assistants, or a trusted person. In principle, you can create a list before the tournament for each participant, specifying the 8 rounds and the distribution of factions per round! This would reduce the workload, in my opinion. We can vote on this.

The goal of the group stage is to have fun. The goal of the playoffs is to identify the strongest player and the strongest group of factions.

It's simple, and we can start in a week, giving a week for promoting the tournament!