Running Home Assistant OS in a virtual machine using the provided VM images is a supported configuration.

From ADR-0015: Installation Method: Home Assistant OS:

Supported Hypervisors

The Home Assistant Operating System can be run on a Hypervisor and thus be run as a virtual machine. The following Hypervisors are supported:

• KVM/QEMU
• VirtualBox
• VMWare
• Xen

We will provide documentation for the following systems build on top of these technologies:

• Proxmox (KVM/QEMU based)
• Unraid (KVM/QEMU based)
• VirtualBox
• VMWare

Might not be the answer you are looking for: I would strongly advise against self-hosting your main email, especially if you are thinking about doing it on an IP address from a residential ISP or VPS/cloud provider. Unfortunately those kind of addresses have bad reputations for spam, and you will run in to significant deliverability issues at minimum. Some providers flat out block port 25, which makes sending and receiving unauthenticated email impossible (which is required to operate an “email provider”).