"Oh totally. I got my brother, who lives on the other side of the world and who's not a dev/sysadmin, just a poweruser, to install Proxmox and he's now using GPU passthrough to have VMs run different AI models (in either Linux or Windows) for image generation, experimenting, etc. He's also got a NAS with RAID etc."

dude this is way more than "power user" you're being unserious.

If you tell a genuine power user, someone comfortable with Windows registry edits, Office macros, maybe some light PowerShell scripting, that they can "totally do what my brother did," and then the actual task list is Proxmox installation, IOMMU group isolation, VFIO stub drivers, GPU passthrough debugging, RAID configuration, and multi-OS VM management, subnetting, raid and HBA configuration, you're setting them up for a brutal wall of frustration.