Importing from blender to unity change the mesh

i have no idea why its happening. on blender the table looks fine.

but when i import to unity it looks like that

i double checked to make sure the legs dont go through the table and they dont in blender. but in unity they do for some reason. and the table upper part looks too flat

Check your normals… top right Overlays → Face Orientation… should be all blue and no red…
…then in Edit Mode: Mesh → Normals → Recalculate…