LUNS and Zvols

What is the best for Trusnas and LUNS or datasets?

A single large luns or smaller individual luns for each VM?

I am currently using ESXI but will be switching to either hyper-v or proxmox but it is 10GB network adapters for ISCSI

If you are doing a VM of TrueNAS, set it up as ‘production’.
You are not explaining what you are expecting this server to be used for. Is TrueNAS, on bare metal, providing storage to VMs on ESXI, Hyper-V or Proxmox or is it running on them?

VIRTUAL