All versions of Windows 10 and 11 can read and write to ReFS partitions. It's just creating new ones that is restricted to certain versions, and booting to ReFS isn't possible with any Windows version. If those were the only drives in the "server" then at least one partition would have to be NTFS.
Win10/11 can also work with a Windows software RAID array, and it would just be automatically detected when you move the disks to another machine. With Windows software RAID1 you can just plug an individual drive in and it will behave like a normal drive, but Disk Management would show a broken array. If it's Windows RAID0, it could possibly show partitions you can't manage since they only function with both disks present, but it also ought to be showing a broken array warning (missing drive in Disk Management).
If it was true hardware RAID there wouldn't even be any visible partitions, but if it used "hybrid" RAID1 (fakeRAID) like is integrated into consumer chipsets (and the very low-end "server" RAID controllers in Dell and other OEM machines like the S100) then Windows could possibly see the partitions and in some cases even be able to work with them despite not having the same controller enabled.
Try using a third-party tool like AOMEI Partition Assistant to view the configuration and properties of the drives and the partitions. That will give you more information about how they're formatted. Are they GPT or MBR? Are they Basic Disks or Dynamic Disks (required for Windows RAID)? Can it read the filesystem type?
Are you able to plug both of them in at the same time to see if they might be picked up correctly when both are available? You can also use recovery tools like DMDE to detect the RAID configuration if there is one. The tool can also recover files if there is a problem, although not if it's a broken RAID0.
If you're trying to recover data for the neighbor, can they not tell you how they were configured?