Hi Imran,
That a film-strip (celluloid or polyester, etc.) has to be reasonably stiff to work in-camera or in a projector is not a secret.
The file you have attached follows not that idea, and there is pretty much no way to make it work, certainly not with UV since the polygons are not following the characteristics of the material to begin with.
What I did was to harvest a Spline from an edge along the whole strip. Main Menu> Mesh> Conversion>Edge Selections to Spline
This spline is then used in a Spline Wrap under a Polygon (strip).
Inside the Spline Wrap, I fiddled a little bit with the Rotation Spline interface. To get the “images” of the filmstrip nearly in a rectangular shape.
You will find two versions, one that uses SDS and one that goes just with the Plane.
A screen-capture of file [11] is also attached, as requested.
https://www.amazon.com/clouddrive/share/L3ZbvUcGJfOJxsrE3ti3ePyu4odEJBzcN1rccUirkbM
I think that is very close to a filmstrip, a little bit adjustment on the rotation of the Spline wrap might improve it even more.
Have a great start into your week.
Stay safe, stay healthy.