Lag when testing out game in Unity Editor

Hi,
Whenever I add a character motor to my object then go into game mode, I always get a whole heap of lag.

Am I doing anything wrong? Will be happy to send over my files if someone can fix it…

Thanks,
Redmug

Yep, there is 1 error : ‘Terrain Splat 0 is null’ What does that even mean?

It is just a terrain with some textures applied, a hexagon for a goal, and a sphere with with character motor and tergeted by a smooth follow script