How different would Windows have been if Windows 11 used ZFS instead of NTFS?

Windows as a storageserver with Storage Spaces is not as bad as you can pool disks of any type or size and set location, redundancy or hot/cold data tiering per Space. If Microsoft would improve usability without deep Powershell knowledge, this would be a first step.

ReFS as a modern alternative to ntfs is the next option. It is included in Windows Server and Windows 11 as dev drive. It offers Copy on Write and bitrot protection like ZFS but lacks many ZFS features like encryption, hybrid pools, sync protection, snaps and easy management of larger arrays.

What makes Windows unique beside superiour ACL management is SMB Direct/RDMA what allows 3-10 Gbyte/s over lan even in workgroups with concurrent users at lowest latency and cpu load. Sadly you need Windows Server for the serverpart (2022/2025 Essentials is fine).

OpenZFS 2.3.0 for Windows is now a release candidate. Still a beta but already quite usable with less bugs per release candidate every vew weeks. Expect release soon.

I do not know if M$ will include OpenZFS one day just like OpenSSH or other projects but storage + Windows is already one of the best storage options. This is the reason why I ported my napp-it cs web-gui from Solaris to Windows for easy Storage Spaces and ZFS management (free for noncommercial use)

It depends on what exactly you have on your Main Computer.

While ZFS might help a little with Storage system it can have problems with some software that is Designed to work well with NTFS.

That said, Win 11 has a Nice feature for itself. If you use another SSD/HD etc. It will be Activaed on the same Motherbaord.

So, buy an SSD, Clone you system to it make ZFS and see if every thing that you need works Better then NFS on it.

If it is Clone to it again you current main system and keep it as a back up and then ZPS your main System,

You can have local fat32, ntfs or Refs disks on ZFS on Windows with a .vhdx virtual harddisk file. Much simpler than any other method and it works even over LAN as a zero config alternative to iSCSI.

OpenZFS on Windows: 2.3.0 pre release rc2

Seems we are near to a release.
Please evaluate, report bugs under Issues or discuss experience under Discussions