Depends on what you want.
I have 2 separate VPN servers, 1 local just for when I logon to an untrusted network and the other to get access to US content.
The US based VPN is a cheap VPS running wireguard and because it's a VPS the IP is not blacklisted by major companies as VPN exit point.
The last 2 elections he did not vote. My guess is that he did not wanted to vote democrats but Trump was too extreme for him.
But that's just my guess.
After you setup the mail gateway you can telnet to port 25 and do the command line mail test and see if mail is delivered to your mail server.
After that is confirmed you change your dns mx records.
It depends a bit on your needs.
My proxmox setup is like multiple nodes (computers) with local (2 drives with ZFS mirrorig), they all use a truenas server as NFS host for data storage.
For some things I use conaitners (LXC) but other thing I use VMs.
Cook needs a new boat