SetTile is too slow

I have 12 total tilemaps I need to set each tile for to load a level. With smaller levels, the loading times are fine, but with larger numbers of tiles, SetTile() is just too slow. I need to be able to save and load larger tilemaps, potentially over 1000x500. So I have a couple questions about how to solve this.
1. is there a built in way to save and load tilemaps that is faster than setting each tile individually
2. can SetTile use multithreading and/or ECS
This isn't a game breaking issue, it's just annoying to have to wait to load a bunch of tiles when going through a door.

 

Use SetTiles or SetTilesBlock. Both of these methods are orders of magnitude faster than SetTile esp when the # grows large and if colliders are also involved.

 

You might also try having the tilemaps be in separate scenes, loaded additively/async. I have multiple-layer tilemaps in scenes where the maps are ~ 300*300 and use this approach. Have not benchmarked this Vs settile though.

 

thats life

tricks:
- load it in advance
- load it in coroutines so the game doesnt freeze
- load the tiles closer to the camera first

think about efficiency, whats the point of loading 1000 tiles deep when the camera only sees 30 tiles at once