Hello there @BoneyThanhy!
Considering options inside the engine, it is possible to divide the floor in multiple tiles using Geometry Scripting, following the guide below:
Personally, I would suggest instead to simply take the mesh to your 3D modeling tool of choice, like Blender, and simply slice the floor in smaller parts. Then re-import the group as an FBX. This will also give you better control of your UV maps.