Nutanix is not especially cheap, in my opinion/experience, nor is it particularly easy to manage and maintain

I have made a comparison in recent weeks between proxmox and xcp-np/Xen Orchestra and for me proxmox is not mature enough for a work in production considering different aspects. Xcp-ng, if I see it as a solid option, especially if you pay for the Xen Orquestra subscription, which in addition to unleashing the integral management of your entire xcp-ng park, also allows you to make backups

Seems to be part of a Nortel Networks DMS Switch https://telephoneworld.org/telephone-switching-systems/northern-telecom-nortel-digital-central-office-switches/

It’s solid enough. I kept them closed to keep them in the original state

Only 4. You need a CD-ROM to complete the installation (https://www.serverbrain.org/troubleshooting-2000/install-by-using-setup-diskettes-and-a-cdrom.html)