“Best map for Heroes of Might and Magic III” (2007).

If there is a link about playability and what tournament or quest maps are, please share it.

Well, it's unlikely to be possible... The concept of playability is quite vague. And here, it's unlikely that you can learn how to create maps that are guaranteed to be playable. It only comes with experience.

As a rule, the playability of a map is largely influenced by the balance of power, which means that the player will be in a state of sufficient tension throughout the game, i.e., the opponent must constantly remind themselves. Because if by the end of the first third of the game, everything is already decided and clear, then further interest disappears... But, on the other hand, you can overdo it and turn the map into a constant race between your cities with the goal of keeping them from being captured, when the opponent is coming from everywhere... :) Such a map is easier to abandon than to finish... Both of these options are not very playable, i.e., not interesting. Finding the golden mean is the task.

To understand what tournament maps are, play at least a dozen tournaments, then you will understand better how they differ from non-tournament maps... Namely, by being more playable... :)