recover data from unfunctioned remaining RAID disks due to RAID controller failure
In this case, you need a new RAID controller of similar type.
Can I even simply attach one of the RAID 1 disk to the desktop system
No. One disk out of a RAID array is different from a normal disk.
Recovery becomes easy if you do not use a hardware RAID controller, but a ZFS software RAID instead. It does nearly all automatically. But you need to do a little more reading tutorials for the first setup.
You say it is mounted. Then you can share it in all the same ways as you would share any other of the VM’s folders.
I am using SMB shares for that (but that is not always the best way ofc).