Airgaps are not just the physical separation of systems, but also auditing and filtering of what goes on to the airgapped machine.

One can get many of the properties of an air gapped system by compartmentalizing ones activities. Only playing media in the media-vm, only surfing the web in the web-vm, and only doing banking and high security stuff in the security-vm. Many of these systems wouldn't need persistent storage. And each one has different requirements, for the VM doing banking one could remove the root certs for everything except the sites you care about. Each VM could be on its own VPN, for the security-vm one could choose a network exit that was closest to the desired endpoint.

Copying media files from a guest to the host would compromise the air gapped machine. The host should not do any general purpose computing and nor should there be an account with special administrator privileges.

Look at https://www.qubes-os.org/