is there a simple way of making simple object fall with “look like animation” of falling piece of paper with waving sides and corners that would interact (collision) with other objects and would bend accordingly. Or only creating an 3d model in blender would work? solution with particles is not an option - there is no way to make particle act like objects (collide, trigger something on collision, scripts…) Please do not judge to hard, I am very new to Unity)))
You can use a rigidbody on your object to make it fall.
If you want parts of your object to bend, you would need a a boned object with (I think) a separate rigidbody on each bone.