The best would be, if you would combine all those filesystems to a single filesystem and mount the single filesystem into Windows. Building some kind of network JBOD is not very performance friendly and has many disadvantages. If you really insist doing so, I would suggest the following.
Configure each of your ten 50TB-NAS systems to serve their individual combined disk space as an iSCSI device to some kind of MasterNAS server.
The MasterNAS server (should be a Linux system) should then combine all 10 iSCSI devices as a btrfs super filesystem.
sudo apt install open-iscsi btrfs-progs (for ubuntu/debian server) for this.
You configure all your 10 NAS to serve their entire disk space as a combined iSCSI device. Example: Your NAS-servers use a hardware raid controller which maps the all disk drives to 1 logical drive. This 1 logical drive is propagated by an iSCSI initiator.
You use your new and performant and independent MasterNAS server which is "collecting/mounting" all 10 iSCSI targets from all 10 NAS servers. I suggest this MasterNAS uses an modern Linux and uses btrfs as filesystem for the iSCSI-NAS-drives. You then just create a super btrfs filesystem in single mode (which is essential some kind of cool JBOD device which uses filesystem level data stipping). You can do this like so:
sudo mkfs.btrfs --data single /dev/sda /dev/sdb /dev/sdc /dev/sdd /dev/sde /dev/sdf /dev/sdg /dev/sdh /dev/sdi /dev/sdj (this combines all 10 drives to a JBOD like linear btrfs filesystem)
You can mount that super btrfs filesystem just by using any of it's devices, like so:
mount /dev/sda /mnt.
The advantage of a btrfs JBOD like device is, should one of the NAS severs going down, your filesystem won't crash, you'll "just lose" the files from the offline NAS server. (Ok' it will crash in default settings, but data recovery is much easier, as file stripping is happening on filesystem level with btrfs)
After doing all this stuff, you install a samba server onto your MasterNAS and share this super btrfs filesystem to your WindowsVM.
PS there is also a free btrfs driver for Windows, but I've no experience with it --> https://github.com/maharmstone/btrfs