The world I spawned in was a mesa biome, but also was next to an ocean, with a huge forest of trees next to it. This made my computer lag very heavily unfortunately. I found a seed for a normal plains/forest biome, and I want to re-create the world my server uses to load with that seed. Is there any way I can erase the sever world and use the seed I found without having to make an entirely new server? Any help is appreciated.
Simply remove the world folder, and set the seed in the server.properties file.
Alternatively, you could remove only the region files, and set the seed in the level.dat file instead, though that requires an NBT editor program. This would only be necessary if you have other things in the world (besides the overworld itself) that you don't want to loose (your inventory, the nether/end, etc…)