Why are you installing TrueNAS? It is tricky to get right on Proxmox or run as a VM. It is usually better installed on bare metal.
You have to set it up to pass the entire controller (HBA) with the disks attached to TrueNAS. TrueNAS needs and wants direct access and control. The same happens for the TrueNAS boot disk. It has to be protected from Proxmox accessing it.
The vmware-checkvm error, just ignore that in the console messages. It’s a normal error and, maybe, goes away if running on vmware.
If you are getting those two addresses for the TrueNAS gui, I am guessing you don’t have the networking setup up correctly on TrueNAS.
I’ll give you some links to read
Virtualize TrueNAS
ZFS Primer, explains the terms for filesystem
Documents section for TrueNAS. You need to choose the version you are using
You might need to visit a forum for Proxmox for some of your questions.