Help with buying server software

Yeah, I recommend ESXi then, and I would stick with CentOS/RHEL, Ubuntu, Debian and FreeBSD for your *nix Vms. Definitely stay away from any exotic or bleeding edge distributions.

If ESXi isn’t an option for some reason, then Proxmox or XCP-ng (full disclosure, I have no experience with XCP but I understand that it’s pretty friendly).