ZFS on Windows is slowly getting better.

I wouldn't actually trust it with data yet, but I suspect the developers would welcome any contributions or effort sent in their direction: https://github.com/openzfsonwindows/ZFSin

(I'm not affiliated, but I think it's a cool project, and I really want it to succeed)

I don't think deduplication can do much of a job on media files which are heavily compressed anyhow.

As for Windows, that's a new one! When I think ZFS I think NAS although I did briefly had it on a laptop with FreeBSD I think.

Dedup is a pretty niche use case for most people.