Rules for organizing, conducting, and participating in online Heroes of Might and Magic III tournaments.

regarding extending deadlines. If a player doesn't meet the deadline, then it only makes sense to consider the date of the game, as this is a violation of the rules in itself. In all other cases, the game should be counted, there is nothing to argue about.

This is only relevant in the case where all players have finished earlier, i.e., it was possible to identify players competing to leave the group with an equal number of points, Berger score, and head-to-head record (a tie) before the deadline – in this case, everything is open for discussion, and a decisive game can be scheduled without any problems. In reality, however, it is unclear until the very end who will advance, and the outcome of one match can change everything.
Run a couple of tournaments – test it in practice.