What would be the minimum and the ideal hardware to host them on a bare metal server using Virtualizor? Will I need 27 Cores, 50GB RAM and 1870GB HDD for hosting the 5 VPSs?
If they are going to be using KVM Linux vpses then 32Gb RAM would be fine for start, assuming only half the RAM would be in use, most of the times, by the vpses.
Similarly for vps disks, if you go with Thin-LVM or File based Qcow2 storage then over-committing would be possible.
But If the RAM and Disk(SSD/NVME) actually get used up to the fullest capacity assigned to them then over-committing will fail (auto-suspending of KVM vps) and eventually you will require to upgrade disk and RAM on server so that vpses can use it.