Dude this literally looks like it was made in 10 minutes. no one is buying this
look adding a subdivision takes 0 minutes to do lazy bones:
STEP 1: open blender and import the model
STEP 2: open the modifiers tab on properties
STEP 3: add modifier: subdivision surface...
and then switch type to simple instead of catmull clark
EDIT:
making your low poly model smoother and high poly is just that