Instead of combining the whole map, making it big and therefore causing more lag, break the map up into smaller regions that you travel to by joining another server
this concept is similar to project slayers
Example: in dsrpg, the will be servers where it’s only akimaya. if you want to travel to rice fields, you open up a menu and click a button that sends you to another server, where the entire map is just rice fields
This allows for maps to be much bigger without causing more lag. However, the concept of exploration while traveling between regions will be lost.