I recommend Ubuntu Server, as IA is known to use that to test Ignition.
I recommend not installing a desktop GUI on the VM. Text console only, and only use that for troubleshooting SSH. Use SSH for all other access and maintenance. (Absolutely required if you are truly determined to master Linux.)
Your server requirements look quite light-duty, except for Perspective. I'd start with 16GB ram and eight vCPUs.
For the SMB connections to external devices, I recommend you set those up with Linux's autofs to dedicated mount points. They will then appear to be local to Ignition, and will be very robust when connections are disrupted (set soft-fail to just a few seconds).
I do recommend you install a full Linux desktop environment on your primary workstation, and move its Windows install into a VM. (I recommend Kubuntu, or other major distro with KDE. I'm currently testing the KDE flavor of Debian Bookworm, fwiw.) Linux's virt-manager has been running all of my Windows instances for about a decade now. (More than a decade... 2012-ish. Windows8 was brand new.)
Where the remote storage is a Linux server, I recommend using sshfs to mount the remote storage, and using autofs to manage that mount on-demand. To be relatively secure, you will need a SSH key pair that is dedicated to this purpose, and on the remote storage side, has its pubkey tweaked to only allow SFTP access, and only to a target folder.