I don't think you're following the topic.

I already said I can't use cubes because they are good for small beam and mine isn't.

I also explained twice that I already have film polarizers and they receive reflections on them and why I want AR coating. You seem to claim polarizer films shouldn't be receiving reflections but they do.

When I write "beam splitter" in the diagram I mean polarizer. A beam splitter can be different types, one of them being "polarizer beam splitter". That's what I'm referring to, same thing.