Big maps ... are so small!

[Triumph Jordi]

The reason you meet at turn 2 on a large map is that they removed the Player distance "Far" option. Although that option did not help much, it did help somewhat. I reckon they removed it because of all the crashes.
You can see the reason why the game became more stable since the last DLC and patches is because they limited the amount of players (from 12 to 9) and removed the aforementioned Player distance "Far" option.

Okay I'm sorry but this is just incorrect. First off, we didn't limit the amount of players in any of our Patches. Age of Wonders 4 has only ever supported 9 Players Max on a Map, regardless of whether they're Human or AI. Secondly we didn't remove any of the Player Distance settings, we renamed the option and settings to better represent what they do. The old Far Player Distance largely aligns with the Very Large Relative Map Size, with some tweaks to create more isolated areas for players. Large Relative Map Size fits in between the old Far and Normal Player Distance and so on.

We've explained before that we went with Relative Maps tied to Distance between Players & Player Numbers because it allows us to maintain the same Player Experience regardless of the map size/number of players.