In the seed, I'm using (-189012993 on 1.17) the nearest woodland monument is like 10,000 blocks away. Buying a woodland explorer map from a villager and looking at it crashes the game. For whatever reason, I am able to load back in with the map loaded correctly and everything fine (possibly because I am realm admin or in creative?) but any other survival player will crash and will not be able to load the game fully as the map causes them to crash.

Killing the player using commands/getting rid of the map out of their inventory will solve this, but that requires commands and isn't really a good solution. I have seen similar issues with trying to use a map from a custom loaded structure where the map is trying to load data from another world, not on realms. Looking at the map will cause the game to crash and can only be solved by removing the anomalous map.